Method for detecting large particles in submicron spherical silicon dioxide slurry

Abstract

The invention relates to a method for detecting large particles in submicron spherical silicon dioxide slurry, which comprises the following steps of: dispersing slurry to be detected uniformly by using an ultrasonic disperser; pouring the uniformly dispersed slurry into a test screen of which the mesh size is more than 5 [mu] m for screening, and washing the residual slurry on the test screen by using a solvent after the slurry is screened; putting the test sieve into a beaker containing a clean solvent, cleaning residual fine powder on the sieve, putting the test sieve into an ultrasonic cleaning machine for ultrasonic cleaning, and drying after cleaning; putting the dried test sieve into an optical microscope for observation, counting the number of large particles on the sieve, measuring the size of the large particles on the sieve, and calculating the size of the large particles on the sieve. Therefore, the accurate number and size of the large particles in the submicron spherical silicon dioxide slurry are obtained. According to the method, the size and the number of particles with the particle size of more than 5 microns in the submicron spherical silicon dioxide slurry product can be accurately detected by cleaning for multiple times and then drying and adopting an optical microscope.

Description

Technical Field

[0001] The invention relates to the technical field of material particle detection and analysis, in particular to a method for detecting large particles in submicron spherical silicon dioxide slurry. Background Art

[0002] In the fields of material testing technology and particle analysis technology, characterization of large particle size and quantity is an important research direction, especially in the production and application of spherical submicron silica slurry products. Accurate detection of the size and quantity of spherical silica large particles is crucial for product quality control and performance optimization. Because the current trend of electronic product development is to become increasingly thinner and shorter, the filler particle size used is required to be finer and the large particle size is required to be smaller. Conventional micron spherical silica cannot meet the needs of some high-end application scenarios such as packaging substrates and laminated films. Submicron spherical silica slurry is required, and the maximum particle size in submicron spherical silica products is required to be smaller and smaller. A very small amount of large particles in the slurry product will affect the reliability of downstream application products. Submicron spherical silica products have a small number of maximum particles and a small maximum particle size. How to check the maximum particle size and number in the product is a technical problem.

[0003] The conventional method of detecting large particles is to detect by sieving and weighing, but this method is generally suitable for detecting products with a particle size greater than 20μm and a large content of large particles. Since the maximum particle size of submicron spherical silica slurry products is small and the quantity is small, the conventional sieving and weighing method will cause the slurry products to agglomerate when sieving, and it is impossible to accurately measure the trace large particles in the product.

[0004] The existing patent "A method for testing particle size distribution of micron-level surface-treated inorganic powder" (patent number: CN117990565A) is to use a laser particle size analyzer to detect the particle size of the product after ultrasonic dispersion of the product, and then judge the size of large particles in the product by the D100 of the test result. Although this method can detect large particles of less than 20μm in the product, the error of testing large particles using this method is large, and the sampling quantity is small, and the representativeness is poor.

[0005] The existing patent "A method for detecting the particle size of silicon carbide micropowder" (patent number: CN103018143B) first uses an optical microscope to observe the sample to infer the sample particle size, and then uses a laser particle size analyzer and a COULTER particle counter to detect the particle size of different intervals according to the particle size. It combines the resistance method and the laser method, but the laser particle size analyzer is limited in accuracy when measuring the size of large particles, resulting in the inability to accurately measure and evaluate the size and number of actual large particles in the sample. This method also has the problem of small sample volume and poor representativeness, and cannot objectively characterize the overall level of the size and number of large particles in the sample.

[0006] The existing technology involving the use of scanning electron microscopes for observation also has the problem of small sampling volume and poor representativeness. Therefore, for products with low large particle content and a maximum particle size greater than 5μm, the existing technology is insufficient in accuracy and objectivity, and it is urgent to develop a more accurate and objective method for characterizing the size and number of large particles. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a more accurate and objective method for detecting large particles in submicron spherical silica slurry in view of the shortcomings of the prior art. The method can accurately detect the size and quantity of particles larger than 5 μm in submicron spherical silica slurry products.

[0008] The present invention is a method for detecting large particles in a submicron spherical silicon dioxide slurry, which is characterized in that the method comprises the following steps:

[0009] (1) Test sieve cleanliness test: Ultrasonic cleaning of the test sieve, and use an optical microscope to check if there is any foreign matter on the surface of the test sieve;

[0010] (2) Use an ultrasonic disperser to disperse the slurry to be tested evenly;

[0011] (3) Pour the evenly dispersed slurry into a test sieve (mesh size is 5-45 μm) for sieving. After the slurry sieving is completed, use a solvent to flush the slurry remaining on the test sieve until there is no slurry remaining on the test sieve;

[0012] (4) Place the test sieve in a beaker containing a clean solvent, gently shake the test sieve to clean the residual fine powder on the sieve, and finally, place the beaker in an ultrasonic cleaning machine for ultrasonic cleaning. After cleaning, place the test sieve containing large spherical silica particles in an oven for drying:

[0013] (5) The dried test sieve is placed under an optical microscope for observation, the number of large particles on the sieve is counted, and the size of the large particles on the sieve is measured, thereby obtaining the accurate number and size of the large particles in the submicron spherical silica slurry.

[0014] The technical problem to be solved by the present invention can be further achieved by the following technical solution: the diameter of the test sieve is 2-20 cm, and the sieve mesh size specification is 5-45 μm.

[0015] The technical problem to be solved by the present invention can also be further achieved by the following technical scheme, wherein the test sieve is inspected for cleanliness before use, and the inspection process is to use an optical microscope to check whether there are foreign objects on the test sieve; if there are foreign objects on the sieve, the test sieve is turned upside down on the bottom of a beaker containing a solvent, and the solvent is placed in the beaker to completely cover the test sieve; then, the beaker is placed in an ultrasonic cleaning machine to clean the foreign objects, and after cleaning, it is placed in an oven to dry, and the test sieve is inspected again using an optical microscope to ensure that there are no visible foreign objects on the test sieve.

[0016] The technical problem to be solved by the present invention can be further achieved by the following technical solution: the ultrasonic power of the ultrasonic cleaning machine used in the cleanliness inspection of the test sieve is 360W.

[0017] The technical problem to be solved by the present invention can be further achieved by the following technical solution: the ultrasonic power of the ultrasonic disperser used in step (2) is 1200W, and the ultrasonic dispersion time is 5-10min.

[0018] The technical problem to be solved by the present invention can be further achieved by the following technical solution. In step (3), the beaker is first placed in an ultrasonic cleaning machine for ultrasonic cleaning for more than 10 minutes, and then placed in an oven at a temperature of 110° C. for drying.

[0019] The technical problem to be solved by the present invention can be further achieved by the following technical scheme, wherein the solvent is one or more of ketones and benzenes.

[0020] The technical problem to be solved by the present invention can be further achieved by the following technical solution, which can detect the number of large particles with a particle size of 5 μm or more in a silicon dioxide slurry product with a large particle content of less than 1 ppm.

[0021] The technical problem to be solved by the present invention can be further achieved by the following technical solution: the total sample amount of the detection exceeds 200g of silicon dioxide slurry.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] First, the present invention uses a test sieve with a mesh size of 5-45 μm to screen and wash the slurry multiple times, and dries it, and observes and measures it through an optical microscope, so as to accurately detect the size and number of particles larger than 5 μm in the spherical submicron silica slurry product, thereby avoiding the accuracy limitation of the particle counter and Malvern laser particle size analyzer when measuring the size of large particles, and also overcomes the loss that may be caused by the scanning electron microscope during the sample preparation and transfer process, thereby improving the measurement accuracy;

[0024] Second, the method of the present invention has a simple operation process, requiring only the use of an optical microscope for observation and measurement, without the need for a complicated sample preparation process, special equipment and technology, and therefore, is low in cost and easy to promote and apply;

[0025] Thirdly, the detection method of the present invention uses a large sample volume and adopts an optical microscope for direct observation and measurement, so that the size and number of the obtained large particles are more objective and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a result diagram obtained by optical microscope detection after 5 tests in Example 1;

[0027] Figure 2 This is the result obtained by using a laser particle size analyzer;

[0028] Figure 3 This is a particle image obtained using a particle counter;

[0029] Figure 4 The results obtained using a scanning electron microscope. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Embodiment 1,

[0032] Step 1: Test sieve cleanliness check

[0033] Use an optical microscope (Olympus BX51) to check whether there are foreign objects on the 10μm test sieve; if there are foreign objects on the sieve, turn the test sieve upside down on the bottom of a beaker containing butanone, and the butanone should completely cover the test sieve. Then put the beaker into an ultrasonic cleaner (KQ-500DB, ultrasonic power of 360W, ultrasonic frequency of 40KHz) to clean the foreign objects. After cleaning, put it into an explosion-proof oven (DHG-9070A, temperature set to 110℃) to dry, and use an optical microscope to check the test sieve again to ensure that there are no visible foreign objects on the test sieve;

[0034] Step 2: Slurry pre-dispersion

[0035] Prepare 200g of 0.5μm spherical silica slurry sample (Jiangsu Lianrui New Materials) with a solid content of 70% and a solvent of butanone. When the slurry is stored for more than 1 month, it is necessary to use an ultrasonic disperser (model JY92-II, ultrasonic power of 1200W, ultrasonic frequency of 20KHz) to disperse it in advance to avoid the presence of some agglomerates in the sample that affect subsequent observations.

[0036] Step 3: Slurry filtration

[0037] Pour the slurry sample in step 2 into a test sieve without foreign matter, use a washing bottle to spray an appropriate amount of butanone to rinse the slurry remaining on the test sieve, then put the test sieve into a beaker containing clean butanone, and gently shake the test sieve to clean the remaining fine powder on the sieve.

[0038] Step 4: Dispersion of the oversize

[0039] Put the test sieve into the beaker containing clean butanone again. Note that the butanone in the beaker cannot cover the sieve frame during the operation. Put the beaker into an ultrasonic cleaning machine for ultrasonic cleaning for 10 minutes. After cleaning, put the test sieve containing large spherical silica particles into an explosion-proof oven for drying for 5 minutes.

[0040] Step 5: Detection of the number and size of large-particle spherical silica.

[0041] Use an optical microscope to observe the large spherical silica particles on the test sieve after drying in step 4, measure their size and record the number of large particles. The specific operation is as follows: adjust the optical microscope to observe foreign matter, operate the stage to move horizontally on the X-axis and Y-axis, observe the overall appearance of the test sieve, and record the size and number of each large spherical silica particle larger than 10μm.

[0042] The above steps are carried out at normal temperature and pressure.

[0043] Through the above steps, the size and number of large spherical silica particles in the spherical silica slurry product can be accurately and objectively characterized, which improves the measurement accuracy and also provides a more objective method for characterizing the size and number of large particles.

[0044] Embodiment 2,

[0045] The difference from Example 1 is that the test sieve aperture used in step 1 is 5 μm. The slurry sample used in step 2 is 400 g of a 0.3 μm spherical silica slurry sample (Jiangsu Lianrui New Materials) with a solid content of 60% and a solvent of cyclohexanone.

[0046] Embodiment 3,

[0047] The difference from Example 1 is that the test sieve aperture used in step 1 is 20 μm. The slurry sample used in step 2 is a 0.8 μm spherical silica slurry sample (Jiangsu Lianrui New Materials) with a solid content of 75% and a solvent of butanone, weighing 200 g.

[0048] Embodiment 4,

[0049] The difference from Example 1 is that the test sieve aperture used in step 1 is 15 μm. The slurry sample used in step 2 is a 0.5 μm spherical silica slurry sample (Jiangsu Lianrui New Materials) with a solid content of 75% and a solvent of toluene, weighing 200 g.

[0050] Embodiment 5,

[0051] The difference from Example 1 is that the test sieve aperture used in step 1 is 45 μm. The slurry sample used in step 2 is 300 g of a 0.8 μm spherical silica slurry sample (Jiangsu Lianrui New Materials) with a solid content of 50% and a solvent of toluene.

[0052] Embodiment 6,

[0053] The difference from Example 1 is that the test sieve aperture used in step 1 is 5 μm. The slurry sample used in step 2 is 500 g, with a solid content of 50%, a solvent of a mixture of acetone and toluene, and a particle size of spherical silica slurry sample of 0.1 μm (Jiangsu Lianrui New Materials)

[0054] Comparative Example 1:

[0055] The difference from Example 1 is that in step (2), 50 g of the slurry is weighed, and the rest is the same as Example 1.

[0056] Comparative Example 2:

[0057] The difference from Example 1 is that the content of particles larger than 10 μm in the slurry in step (2) is 2 ppm, and the rest is the same as Example 1.

[0058] Comparative Example 3:

[0059] The difference from Example 1 is that in step (2), no ultrasonic dispersion test is performed after the slurry is weighed, and the rest is the same as Example 1.

[0060] Comparative Example 4:

[0061] The slurry obtained in step (2) in Example 1 was measured using a sieving weighing method.

[0062] Comparative Example 5:

[0063] The slurry obtained in step (2) in Example 1 was tested using a laser particle size analyzer (Mastersizer 3000).

[0064] Comparative Example 6:

[0065] The slurry obtained in step (2) in Example 1 was tested using a particle counter (specification model W-3000) to detect the particle size distribution and number.

[0066] Comparative Example 7:

[0067] The slurry obtained in step (2) in Example 1 was dried and then examined using a scanning electron microscope (specification model JSM-IT200) to measure the particle size and number.

[0068] The present embodiments 1-6 and comparative examples 1-3 were tested 5 times respectively, and the maximum particle size and the number of large particles larger than the sieve aperture were recorded. The results obtained in the embodiments 1-6 and comparative example 1 are shown in Tables 1 to 7 below. At the same time, the results obtained by optical microscope detection in Table 1 are given as follows: Figure 1 In Comparative Example 2, due to the high content, it was impossible to accurately count the particles. In Comparative Example 3, due to the lack of ultrasonic dispersion detection of the slurry, there were many agglomerates in the sieve, and the particles could not be counted and detected. In Comparative Example 4, the result of the sieving weighing method was ND, and the analytical balance could not accurately identify the difference in the weight of the sieve before and after the slurry was sieved.

[0069] In addition, a laser particle size analyzer, a particle counter (specification model W-3000), and a scanning electron microscope (specification model JSM-IT200) were used to detect the particle size of the slurry obtained in step (2) of Example 1. The results obtained by using the laser particle size analyzer are as follows: Figure 2 The results obtained using a particle counter are shown in Figure 3 The results obtained by scanning electron microscopy are shown in Figure 4 shown.

[0070] Table 1

[0071]

[0072] Table 2

[0073]

[0074] Table 3

[0075]

[0076] Table 4

[0077]

[0078] Table 5

[0079]

[0080]

[0081] Table 6

[0082]

[0083] Table 7

[0084]

[0085] After comparison, the following results were obtained:

[0086] Reference Figure 2 , using a laser particle size analyzer for testing, 2-3 drops of spherical silica slurry are needed, and the detection is also not objective, and the large particle size cannot be accurately obtained. Figure 2 The detected particle size distribution D100 = 1.65 μm can only be used as a reference value.

[0087] Reference Figure 3 , the particle counter was used for detection, and the above detection data was captured in a volume of only 0.841 ml, which is not objective. In summary, the large particle level of spherical silica slurry cannot be objectively evaluated.

[0088] Reference Figure 4 , using scanning electron microscope for detection, using a plastic dropper to absorb the slurry, the first drop into the drying dish, after drying, use conductive glue to stick it, and observe it under the electron microscope. When it is magnified 2000 times, large particles of about 20μm can be observed, but after magnification 5000 times, it can be clearly observed. This method has limitations, and there may be a situation where large particles are wrapped by small particles and cannot be observed, and there are also situations where the observation results are not objective.

[0089] The above-described embodiments can accurately detect the size and number of particles larger than 5 μm in the submicron spherical silica slurry product by using the test sieve and optical microscope described in the present invention, and have good objectivity through multiple parallel sample comparisons. It solves the problem that the particle counter and laser particle size analyzer in the prior art are limited in accuracy when measuring the size of large particles, and may not be able to accurately measure the size and number of large particles; the use of a scanning electron microscope for observation requires the sample to be prepared on a carbon tape, and there is loss during the transfer process, which may lead to inaccurate measurement results; the sample volume in the prior art is too small each time, and it cannot objectively reflect the overall level of large particles in the actual product. The large particle measurement value itself has a certain degree of randomness, which further illustrates the problem that the measurement value is not objective; the prior art lacks accuracy and objectivity in the characterization of large particle size and number.

Claims

1. A method for detecting large particles in a submicron spherical silica slurry, characterized in that: The method can detect the number and size of large particles with a particle size of 5 μm or more in a silicon dioxide slurry product with a large particle content of less than 1 ppm.

2. The method for detecting large particles in submicron spherical silica slurry according to claim 1, characterized in that: The total sample amount tested was more than 200g of silica slurry.

3. A method for detecting large particles in a submicron spherical silica slurry, characterized in that: The method comprises the following steps, (1) Test sieve cleanliness test: Ultrasonic cleaning of the test sieve, and use an optical microscope to check if there is any foreign matter on the surface of the test sieve; (2) Pre-dispersion of slurry: Use an ultrasonic processor to disperse the test slurry evenly; (3) Slurry filtration: pour the slurry dispersed evenly in step (2) into a test sieve for sieving, and use a solvent to wash the slurry remaining on the test sieve; (4) Dispersion of the material on the sieve: Place the test sieve in step (3) into a beaker containing a clean solvent, and ultrasonically disperse the fine powder on the test sieve; (5) Large particle detection: Place the test sieve containing large spherical silica particles in step (4) into an oven for drying. Place the dried test sieve on an optical microscope for observation. Count the number of large particles on the sieve and measure the size of the large particles on the sieve, thereby obtaining the accurate number and size of large particles in the submicron spherical silica slurry.

4. The method for detecting large particles in submicron spherical silica slurry according to claim 3, characterized in that: The test sieve described in step (1) has an aperture of 5-45 μm and a diameter of 2-20 cm.

5. The method for detecting large particles in submicron spherical silica slurry according to claim 3, characterized in that: The power of the ultrasonic disperser used in step (2) is 1200 W, and the ultrasonic dispersion time is 5-10 min.

6. The method for detecting large particles in submicron spherical silica slurry according to claim 3, characterized in that: The ultrasonic dispersion equipment described in step (4) is an ultrasonic cleaning machine with an ultrasonic power of 360w and an ultrasonic time of ≥10min.

7. The method for detecting large particles in submicron spherical silica slurry according to any one of claim 3, characterized in that: The solvent is one or more of ketone and benzene solvents.

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