A method for identifying silicone adhesive filler

Abstract

The present invention discloses a method for identifying an organic silicone adhesive filler, and belongs to the technical field of filler identification. The method comprises the following steps: purifying the organic silicone adhesive filler to be identified; attaching part of the purified organic silicone adhesive filler to the surface of a conductive adhesive to obtain sample A; sealing the remaining part of the purified organic silicone adhesive filler after making sample A, making a metallographic slice exposing the cross section of the filler particles, and obtaining sample B; analyzing and identifying the filler components in samples A and B respectively. The method can effectively avoid the interference of organic silicon components on the identification effect, realize the identification of fillers from two dimensions of surface and cross section, obtain a variety of information for identifying fillers such as size, morphology, structure, element distribution and phase composition, and quickly obtain accurate identification results.

Description

Technical Field

[0001] The invention relates to the technical field of filler identification, and in particular to a method for identifying an organic silicone adhesive filler. Background Art

[0002] Silicone adhesives have the characteristics of small space occupation, light overall weight, uniform stress distribution, etc. They also show excellent environmental stability and have good tolerance to environmental stresses such as high temperature, low temperature, ultraviolet light, salt spray, oxygen, vibration, organic solvents, etc. In addition, the addition of special fillers can also make it have special conductive properties such as thermal conductivity, electrical conductivity, and magnetic conductivity.

[0003] Filler-type silicone adhesives such as thermal conductive silicone, conductive silicone, and magnetic conductive silicone are widely used in high-end manufacturing fields such as aerospace, weapons and equipment, and electronic manufacturing. Their fillers are mostly inorganic compounds, such as metal powders, ceramic particles, etc. Fillers are the core technology of filler-type silicone adhesives, an important factor affecting their performance and quality, and the main reason for their high production costs.

[0004] In recent years, as the focus of manufacturing development has shifted from "quantity expansion" to "quality improvement", the high-end manufacturing field has placed increasingly higher requirements on the quality of thermally conductive silicone, electrically conductive silicone and magnetically conductive silicone. However, the quality of related products on the market is uneven. There are reasons for the unstable quality of fillers due to imperfect technology, and there are also the phenomenon of lawless elements using inferior fillers to pass off inferior products as good ones and disrupting the market. Whether from the perspective of improving product quality or from the perspective of regulating market order, there is an application demand for identifying organic silicone adhesive fillers.

[0005] At present, there are no standards for identifying silicone adhesive fillers at home and abroad.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a method for identifying silicone adhesive fillers to solve the above technical problems.

[0008] This application can be implemented as follows:

[0009] The present application provides a method for identifying an organic silicone adhesive filler, comprising the following steps: purifying the organic silicone adhesive filler to be identified;

[0010] The partially purified organic silicone adhesive filler is attached to the surface of the conductive adhesive to obtain sample A; the remaining purified organic silicone adhesive filler is sealed after being made into sample A, and a metallographic section exposing the cross section of the filler particles is made to obtain sample B;

[0011] The filler components in samples A and B were analyzed and identified respectively.

[0012] In an optional embodiment, the purification includes: centrifuging the uncured organic silicone adhesive containing the filler to be identified, collecting the precipitate, and removing the organic silicone in the precipitate.

[0013] In an optional embodiment, removing the organosilicon in the precipitate includes: dissolving the organosilicon in the precipitate, separating the solid from the liquid, and drying the solid phase to obtain an organosilicon-free silicone adhesive filler.

[0014] In an optional embodiment, the centrifugation is performed at a speed not less than 4000 r / min for at least 5 min.

[0015] In an optional embodiment, the centrifugation is performed at 4000-6000 r / min for 5-10 min.

[0016] In an optional embodiment, the solvent used to dissolve the organosilicon in the precipitate includes at least one of petroleum ether, n-hexane, cyclohexane, dichloromethane and benzene.

[0017] In an alternative embodiment, the volume of the solvent used for dissolution is at least 10 times the volume of the precipitate.

[0018] In an optional embodiment, the removal of the organosilicon in the precipitate ends when no characteristic absorption peak of the organosilicon is observed in the infrared absorption spectrum of the solid phase.

[0019] In an optional embodiment, the endpoint judgment index is: under the detection conditions that meet the general rules of infrared spectroscopy analysis methods of GB / T 6040-2019, the 1000cm -1 ~1100cm -1 The absorbance of the absorption peak between them is less than 0.05.

[0020] In an optional embodiment, the drying of the solid phase is performed in a vacuum environment at 45-60° C. for 24-48 hours.

[0021] In an optional embodiment, the preparation of sample A includes: contacting the purified organic silicone adhesive filler with the bonding surface of a conductive tape for scanning electron microscope testing, and removing unbonded filler particles.

[0022] In an optional embodiment, the purified organic silicone adhesive filler forms a loose thin layer structure on the bonding surface of the conductive tape.

[0023] In an optional embodiment, before contacting with the purified organic silicone adhesive filler, the method further includes: fixing the conductive tape on a hard substrate.

[0024] In an alternative embodiment, the rigid substrate comprises a glass slide, a rigid aluminum sheet, or a rigid plastic sheet.

[0025] In an optional embodiment, during the preparation of sample B, the material used to seal sample A is epoxy resin.

[0026] In an optional embodiment, after encapsulation, the encapsulated sample is ground and polished in a direction perpendicular to the conductive adhesive bonding surface to obtain a metallographic slice exposing the cross section of the filler particles.

[0027] In an optional embodiment, the analysis and identification of the filler components includes at least one of the morphology, structural size, element distribution and phase composition of the filler particles.

[0028] In an optional embodiment, a scanning electron microscope and an energy dispersive spectrometer are used to detect and analyze the morphology, structural size and element distribution of the filler particles; and / or an X-ray diffractometer is used to detect and analyze the phase composition of representative filler particles.

[0029] In an optional embodiment, the morphology, structural size and element distribution of the filler particles are detected and analyzed according to the energy spectrum quantitative analysis of microbeam analysis in GB / T17359-2012 and the general rules of scanning electron microscopy method at micrometer length in GB / T16594-2008.

[0030] In an optional embodiment, the phase composition of representative filler particles is detected and analyzed according to JY / T 0587-2020 General Rules for Polycrystalline X-ray Diffraction Methods.

[0031] The beneficial effects of this application include:

[0032] The method provided in the present application can effectively avoid the interference of silicone components on the identification effect by purifying, sampling, and detecting and analyzing the organic silicone adhesive filler to be identified in sequence, realize the identification of the filler from two dimensions of surface and cross-section, and quickly obtain accurate identification results. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 This is a schematic diagram of the structure of Sample A in Example 1;

[0035] Figure 2This is a schematic diagram of the structure of Sample B in Example 1;

[0036] Figure 3 This is the mapping result diagram of the identification product when the filler is not purified in Experimental Example 1;

[0037] Figure 4 This is the mapping result diagram of the reference product when the filler is not purified in Experimental Example 1;

[0038] Figure 5 This is the mapping result diagram of the identified product after the filler is purified in Experimental Example 1;

[0039] Figure 6 This is the mapping result diagram of the reference product after the filler is purified in Experimental Example 1;

[0040] Figure 7 is a representative scanning electron microscope image of a cross section of the aluminum silver-plated filler in Experimental Example 2;

[0041] Figure 8 Another representative scanning electron micrograph of the cross section of the aluminum silver-plated filler in Experimental Example 2.

[0042] Icons: 1-filler particles; 2-conductive adhesive; 3-hard substrate; 4-epoxy resin; 5-silver plating; 6-aluminum inside the filler. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0044] The identification method of the organic silicone adhesive filler provided in this application is specifically described below.

[0045] The present application proposes a method for identifying an organic silicone adhesive filler, comprising the following steps: purifying the organic silicone adhesive filler to be identified;

[0046] The partially purified organic silicone adhesive filler is attached to the surface of the conductive adhesive to obtain sample A; the remaining purified organic silicone adhesive filler is sealed after being made into sample A, and a metallographic section exposing the cross section of the filler particles is made to obtain sample B;

[0047] The filler components in samples A and B were analyzed and identified respectively.

[0048] In the above process, the purification includes: centrifuging the uncured organic silicone adhesive containing the filler to be identified, collecting the precipitate, and removing the organic silicone in the precipitate.

[0049] For reference, centrifugation may be performed at a speed of not less than 4000 r / min for at least 5 min to ensure that the filler particles are fully precipitated.

[0050] For example, the centrifugal speed may be 4000 r / min, 4500 r / min, 5000 r / min, 5500 r / min or 6000 r / min, or other speeds exceeding 6000 r / min.

[0051] The centrifugation time can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 12 min, 15 min, 20 min, 25 min or 30 min, etc., or other times exceeding 5 min.

[0052] In some preferred embodiments, the centrifugation is performed at 4000-6000 r / min for 5-10 min.

[0053] For reference, removing the organosilicon in the precipitate may include: dissolving the organosilicon in the precipitate, separating the solid from the liquid, and drying the solid phase to obtain an organosilicon-free silicone adhesive filler.

[0054] The solvent for dissolving the organosilicon in the precipitate may illustratively include at least one of petroleum ether, n-hexane, cyclohexane, dichloromethane and benzene.

[0055] Preferably, at least 10 times (such as 10 times, 12 times, 15 times or 20 times, etc.) the volume of the above solvent as that of the precipitate is added to the centrifuge tube containing the precipitate to fully dissolve the organic small molecules in the organic silicone adhesive.

[0056] In some embodiments, the solid-liquid separation may also be performed by centrifugation, with the centrifugal speed preferably being not less than 4000 r / min and the centrifugal time preferably being not less than 5 min.

[0057] In a preferred embodiment, the above process of adding solvent to the precipitate, mixing, and collecting the solid phase by solid-liquid separation is repeated to ensure that the precipitate does not contain organosilicon. For example, the number of repetitions may be 1, 2 or more, depending on the residual organosilicon in the precipitate.

[0058] In the present application, the removal of the organosilicon in the precipitate is terminated when no characteristic absorption peak of the organosilicon is observed in the infrared absorption spectrum of the solid phase.

[0059] Specifically, the endpoint judgment index is: under the detection conditions that meet the general rules for infrared spectroscopy analysis methods of GB / T 6040-2019, the 1000cm -1 ~1100cm -1 The absorbance of the absorption peak between them is less than 0.05.

[0060] The above endpoint judgment indicators can ensure that the silicone component in the precipitate is small enough to avoid interference with the subsequent identification process.

[0061] Furthermore, the solid phase can be dried for 24-48 hours under a vacuum environment at 45-60° C. Specifically, the precipitate can be spread in a clean culture dish and dried under the above conditions to ensure that the precipitate is fully dried and dispersed to avoid agglomeration of filler particles.

[0062] By purifying the filler of the organic silicone adhesive to be identified so as to separate the filler from the organic silicone adhesive, the interference of the organic silicone component on the identification effect can be effectively avoided, the difficulty of subsequent analysis and identification can be reduced, and the accuracy of the identification results can be improved.

[0063] In the present application, the preparation of sample A includes: contacting the purified organic silicone adhesive filler with the bonding surface of the conductive tape used for scanning electron microscope testing, and removing the filler particles that are not bonded.

[0064] Before contacting with the purified organic silicone adhesive filler, the method further includes: fixing the conductive tape on a hard substrate. The hard substrate may exemplarily include a glass slide, a hard aluminum sheet or a hard plastic sheet.

[0065] The hard substrate has a certain strength and is not easily deformed or damaged. By fixing the conductive tape on the hard substrate, the conductive adhesive can be prevented from undergoing a large deformation, which would cause the filler particles bonded thereon to fall off.

[0066] In some specific embodiments, the preparation of sample A can refer to the following method: cut the conductive tape used in the scanning electron microscope test, fix one side of it on a hard substrate, peel off the protective layer on the other side to expose its sticky bonding surface, and then put it into a sealed container filled with purified organic silicone adhesive filler powder, shake the sealed container to make the sticky bonding surface of the conductive adhesive fully contact with the purified organic silicone adhesive filler, after taking it out, blow the surface of the conductive adhesive with a clean nitrogen flow to remove the unfixed filler particles, and obtain a loose thin layer structure formed by the filler particles on the surface of the conductive adhesive. The sample obtained at this time is sample A.

[0067] It should be noted that by forming a loose thin layer structure of the filler on the surface of the conductive adhesive, the filler can be distributed over the entire surface of the conductive tape while avoiding the interference of filler particle accumulation on the identification effect. Then, after grinding and slicing, the filler particles can be easily found at the interface between the conductive tape and the epoxy resin.

[0068] In the process of preparing sample B in the present application, the material used to seal sample A can be exemplarily epoxy resin.

[0069] After sealing, the sealed sample is ground and polished in a direction perpendicular to the conductive adhesive bonding surface to obtain a metallographic slice exposing the cross section of the filler particles. The sample obtained at this time is sample B.

[0070] Furthermore, the filler components in samples A and B were analyzed and identified using specific analytical methods.

[0071] For reference, the analysis and identification of filler components includes at least one of the morphology, structural size, element distribution and phase composition of filler particles. The corresponding analysis and identification instruments include scanning electron microscope, energy dispersive spectrometer and X-ray diffractometer.

[0072] Specifically, a scanning electron microscope and an energy dispersive spectrometer were used to detect and analyze the morphology, structural size, and element distribution of the filler particles in samples A and B; representative filler particles were selected, and then an X-ray diffractometer was used to detect and analyze the phase composition of the selected representative filler particles. The filler of the silicone adhesive was identified through the analyzed filler particle information.

[0073] Preferably, the morphology, structural size, and element distribution of the filler particles are detected and analyzed according to the energy spectrum quantitative analysis of microbeam analysis in GB / T17359-2012 and the general principles of scanning electron microscopy methods for micrometer-level length in GB / T 16594-2008. The physical phase composition of representative filler particles is detected and analyzed according to the general principles of polycrystalline X-ray diffraction methods in JY / T 0587-2020 to ensure the reliability of the identification results.

[0074] As mentioned above, the identification method provided in the present application can effectively avoid the interference of silicone components on the identification effect, realize the identification of fillers from two dimensions: surface and cross-section, obtain a variety of information for identifying fillers such as size, morphology, structure, element distribution and phase composition, and obtain accurate identification results.

[0075] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0076] Example 1

[0077] This embodiment provides a method for identifying an organic silicone adhesive filler, comprising the following steps:

[0078] S1. First, the uncured organic silicone adhesive containing fillers is separated and purified through a specific purification process to obtain a purified organic silicone adhesive filler.

[0079] Specifically: the uncured organic silicone adhesive containing fillers was centrifuged (centrifugal speed of 5000r / min, centrifugal time of 10min), the precipitate was collected in a centrifuge tube, petroleum ether 15 times the volume of the precipitate was added to the centrifuge tube, and after thorough mixing, the mixed solution was centrifuged (5000r / min, 10min) and the solid phase was collected, and the above process of adding petroleum ether to the precipitate, thorough mixing, centrifugal collection of the solid phase was repeated until the infrared absorption spectrum of the solid phase at 1000cm was found to be satisfactory under the test conditions of GB / T 6040-2019 General Rules for Infrared Spectroscopic Analysis Methods. -1 ~1100cm -1 The absorbance of the absorption peak between the two is less than 0.05. The final precipitate is spread in a clean culture dish, placed in a vacuum environment at 45°C for 24 hours, and dried to obtain the purified organic silica adhesive filler.

[0080] S2. Prepare sample A and sample B through a specific sampling process.

[0081] Specifically: a conductive adhesive tape 2 used in a scanning electron microscope test is cut, one side of the conductive adhesive tape is fixed on a hard substrate 3 (glass slide), and the protective layer on the other side is peeled off to expose the sticky bonding surface, and then the conductive adhesive tape is placed in a sealed container filled with purified organic silicone adhesive filler powder, and the sealed container is shaken to make the sticky bonding surface of the conductive adhesive tape 2 fully contact with the purified organic silicone adhesive filler. After taking it out, the surface of the conductive adhesive tape 2 is purged with a clean nitrogen flow to remove the unfixed filler particles 1, and a loose thin layer structure formed by the filler particles 1 on the surface of the conductive adhesive tape 2 is obtained. The sample obtained at this time is sample A (such as Figure 1 ); another sample A is sealed with epoxy resin 4, ground and polished in a direction perpendicular to the bonding surface of the conductive adhesive 2, and a metallographic section is made to expose the cross section of the filler particle 1 to obtain sample B (as shown in FIG. Figure 2 shown).

[0082] S3. Analyze and identify the filler components in samples A and B.

[0083] Specifically: First, according to the relevant requirements of GB / T17359-2012 microbeam analysis energy spectrum quantitative analysis and GB / T 16594-2008 general rules for scanning electron microscopy methods at micron level, sample A and sample B are analyzed using a scanning electron microscope and an energy spectrometer to obtain information such as the morphology, structural size, and element distribution of filler particles 1, and representative filler particles 1 are selected for X-ray diffractometer detection; then, according to the relevant requirements of JY / T 0587-2020 general rules for polycrystalline X-ray diffraction methods, an X-ray diffractometer is used to analyze representative filler particles 1 to obtain the phase composition information of the filler; finally, this information is combined to identify the filler of the silicone adhesive.

[0084] Example 2

[0085] The difference between this embodiment and embodiment 1 is that the centrifugal speed is 4000 r / min and the centrifugal time is 5 min.

[0086] Example 3

[0087] The difference between this embodiment and embodiment 1 is that the solvent is a mixture of n-hexane and cyclohexane in a ratio of 1:1.

[0088] Example 4

[0089] The difference between this embodiment and embodiment 1 is that the solvent is dichloromethane.

[0090] Example 5

[0091] The difference between this embodiment and embodiment 1 is that the solvent is benzene.

[0092] Example 6

[0093] The difference between this embodiment and embodiment 1 is that the amount of the solvent is 10 times the volume of the precipitate.

[0094] Example 7

[0095] The difference between this embodiment and embodiment 1 is that the hard substrate 3 is a hard aluminum sheet.

[0096] Example 8

[0097] The difference between this embodiment and embodiment 1 is that the hard substrate 3 is a hard plastic sheet.

[0098] Test Example 1

[0099] An organic silicone adhesive with alumina microspheres as filler was selected as a reference product. Half of the alumina microsphere filler in the organic silicone adhesive was replaced with silica microspheres in the laboratory, and an "adulterated" organic silicone adhesive was prepared using the same process as an identification product.

[0100] Without purifying the filler, the comparison results of mapping (a working mode of scanning electron microscope and energy spectrometer that can reflect the distribution of different elements) of the identification product and the reference product are as follows Figure 3 and Figure 4 As shown; after the filler is purified, the mapping comparison results of the identification product and the reference product are as follows Figure 5 and Figure 6 shown.

[0101] Figure 3 and Figure 4 The mapping results for the identification product and the reference product respectively, where the color close to grayish white represents silicon, and the color close to black represents aluminum.

[0102] Depend on Figure 3 and Figure 4 By comparison, it can be seen that when the filler is not purified, there is no obvious difference in the mapping results between the identification product and the reference product, and the "adulterated" silica microspheres cannot be clearly identified intuitively.

[0103] Similarly, Figure 5 and Figure 6 The mapping results for the identification product and the reference product respectively, where the color close to grayish white represents silicon, and the color close to black represents aluminum.

[0104] Depend on Figure 5 and Figure 6 By comparison, it can be seen that after the filler is purified, the mapping results of the identification product and the reference product are significantly different, and the "adulterated" silica microspheres can be easily and clearly identified.

[0105] Test Example 2

[0106] A certain filler is an organic silicone adhesive coated with aluminum silver, and sample B is prepared according to the method provided in Example 1. Its representative picture under a scanning electron microscope is as follows: Figure 7 and Figure 8 As shown, the results show that the coating structure of the filler can be clearly identified. Specifically, the coating is a silver coating 5, and the interior thereof corresponds to the aluminum 6 inside the filler.

[0107] In summary, the method provided in the present application can effectively avoid the interference of silicone components on the identification effect, realize the identification of fillers from two dimensions: surface and cross-section, obtain a variety of information for identifying fillers such as size, morphology, structure, element distribution and phase composition, and quickly obtain accurate identification results.

[0108] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for identifying a silicone adhesive filler, characterized in that: The method comprises the following steps: purifying the organic silica gel adhesive filler to be identified; The partially purified organic silicone adhesive filler is attached to the surface of the conductive adhesive to obtain sample A; the remaining purified organic silicone adhesive filler is sealed after being made into sample A, and a metallographic section exposing the cross section of the filler particles is made to obtain sample B; Analyzing and identifying the filler components in the sample A and the sample B respectively; Purification includes: centrifuging an uncured organic silicone adhesive containing a filler to be identified, collecting a precipitate, and removing the organic silicone in the precipitate; removing the organic silicone in the precipitate includes: dissolving the organic silicone in the precipitate, separating the solid from the liquid, and drying the solid phase to obtain an organic silicone adhesive filler free of organic silicone; the centrifugation is performed at least 5 minutes at a speed of not less than 4000 r / min; the solvent used to dissolve the organic silicone in the precipitate is selected from at least one of petroleum ether, n-hexane, cyclohexane, dichloromethane and benzene; the volume of the solvent used for dissolution is at least 10 times the volume of the precipitate; The removal of the organosilicon in the precipitate is terminated when no characteristic absorption peak of the organosilicon is observed in the infrared absorption spectrum of the solid phase; the judgment index of the endpoint is: under the detection conditions that meet the general rules of infrared spectroscopy analysis methods of GB / T6040-2019, the peak at 1000cm in the spectrum -1 ~1100cm -1 The absorbance of the absorption peak between is less than 0.05; The solid phase is dried in a vacuum environment at 45-60° C. for 24-48 hours; The preparation of sample A comprises: contacting the purified organic silicone adhesive filler with the bonding surface of the conductive tape used for scanning electron microscope testing, and removing the unbonded filler particles; the purified organic silicone adhesive filler forms a loose thin layer structure on the bonding surface of the conductive tape; The analysis and identification of the filler components includes at least one of the morphology, structural size, element distribution and phase composition of the filler particles.

2. The identification method according to claim 1, characterized in that: Centrifugation was performed at 4000-6000 r / min for 5-10 min.

3. The identification method according to claim 1, characterized in that: Before contacting with the purified organic silicone adhesive filler, the method further includes: fixing the conductive tape on a hard substrate.

4. The identification method according to claim 3, characterized in that: The hard substrate includes a glass slide, a hard aluminum sheet or a hard plastic sheet.

5. The identification method according to claim 1, characterized in that: During the preparation of sample B, the material used to seal the sample A is epoxy resin.

6. The identification method according to claim 5, characterized in that: After sealing, the sealed sample is ground and polished in a direction perpendicular to the conductive adhesive bonding surface to obtain a metallographic slice exposing the cross section of the filler particles.

7. The identification method according to claim 1, characterized in that: The morphology, structural size and element distribution of the filler particles are detected and analyzed using a scanning electron microscope and an energy dispersive spectrometer; and / or, the phase composition of representative filler particles is detected and analyzed using an X-ray diffractometer.

8. The identification method according to claim 7, characterized in that: The morphology, structural size and element distribution of the filler particles are detected and analyzed according to the quantitative analysis of the energy spectrum method of microbeam analysis in GB / T17359-2012 and the general rules of scanning electron microscopy method at micron length in GB / T16594-2008.

9. The identification method according to claim 8, characterized in that: The phase composition of representative filler particles was detected and analyzed according to the general rules of polycrystal X-ray diffraction method JY / T0587-2020.

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