CN114923752A - Method for identifying organic silicon adhesive filler - Google Patents

Abstract

The invention discloses an identification method of an organic silica gel adhesive filler, and belongs to the technical field of filler identification. The method includes the following steps: purifying the organic silica gel adhesive filler to be identified; attaching the partially purified organic silica gel adhesive filler to the surface of the conductive adhesive to obtain sample A; and preparing the remaining part of the purified organic silica gel adhesive filler into A After the sample is solid-sealed, a metallographic section exposing the cross-section of the filler particles is made to obtain sample B; the filler components in sample A and sample B are analyzed and identified respectively. This method can effectively avoid the interference of silicone components on the identification effect, realize the identification of fillers from two dimensions of surface and cross-section, and obtain various information such as size, morphology, structure, element distribution and phase composition for identification of fillers , quickly obtain accurate identification results.

Description

A kind of identification method of silicone adhesive filler

technical field

The invention relates to the technical field of filler identification, in particular to a method for identification of an organic silica gel adhesive filler.

Background technique

Silicone adhesive has the characteristics of small footprint, light overall weight, uniform stress distribution, etc. It also shows excellent environmental stability, and has good environmental stress such as high temperature, low temperature, ultraviolet, salt spray, oxygen, vibration, organic solvent, etc. In addition, adding special fillers can also make it have special conduction properties such as thermal conductivity, electrical conductivity, and magnetic conductivity.

Thermally conductive silica gel, conductive silica gel, magnetic conductive silica gel and other filler-type silicone adhesives are widely used in high-end manufacturing fields such as aerospace, weaponry and electronic manufacturing. Most of the fillers are inorganic compounds, such as metal powders, ceramic particles, etc. The fillers are fillers The core technology of silicone adhesive is an important factor affecting its performance and quality, and it is also the main reason for its high production cost.

In recent years, as the focus of manufacturing development has changed from "quantity expansion" to "quality improvement", the high-end manufacturing field has higher and higher quality requirements for thermally conductive silicone, conductive silicone and magnetically conductive silicone. The quality of the products is mixed. There are not only the reasons for the unstable quality of fillers due to imperfect technology, but also the phenomenon that criminals use inferior fillers to fill the market with inferior products, whether it is from the perspective of improving product quality or from the perspective of regulating market order. , there are application requirements for the identification of silicone adhesive fillers.

At present, there is no standard for the identification of silicone adhesive fillers at home and abroad.

In view of this, the present invention is proposed.

SUMMARY OF THE INVENTION

The purpose of this invention is to provide a kind of identification method of organic silica gel adhesive filler to solve the above-mentioned technical problem.

This application can be implemented as follows:

The application provides a method for identifying an organic silica gel adhesive filler, comprising the following steps: purifying the organic silica gel adhesive filler to be identified;

The partially purified silicone adhesive filler was attached to the surface of the conductive adhesive to obtain sample A; the remaining part of the purified silicone adhesive filler was made into sample A and then solid-sealed to make a metallographic section exposing the cross section of the filler particle. get B sample;

The filler components in sample A and sample B were analyzed and identified.

In an alternative embodiment, purifying includes centrifuging the uncured silicone adhesive containing the filler to be identified, collecting the precipitate, and removing the silicone from the precipitate.

In an optional embodiment, removing the organosilicon in the precipitate includes: dissolving the organosilicon in the precipitate, solid-liquid separation, and drying the solid phase to obtain an organosilicon adhesive filler without organosilicon.

In an optional embodiment, the centrifugation is performed at a condition of not less than 4000 r/min for at least 5 min.

In an alternative embodiment, the centrifugation is performed at 4000-6000 r/min for 5-10 min.

In an optional embodiment, the solvent for dissolving the organosilicon in the precipitate includes at least one of petroleum ether, n-hexane, cyclohexane, dichloromethane and benzene.

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

In an optional embodiment, the removal of the organosilicon in the precipitate takes as the end point that no characteristic absorption peak of organosilicon can be observed in the infrared absorption spectrum of the solid phase.

In an optional embodiment, the judgment index of the end point is: under the detection conditions meeting the general rules of GB/T 6040-2019 infrared spectroscopy analysis methods, the absorbance of the absorption peak between 1000cm ^-1 and 1100cm ^-1 in the spectrum is less than 0.05.

In an optional embodiment, the drying of the solid phase is carried out under a vacuum environment of 45-60° C. for 24-48 hours.

In an optional embodiment, the preparation of sample A includes: contacting the purified silicone adhesive filler with the adhesive surface of the conductive tape used for scanning electron microscopy testing, and removing unbonded filler particles.

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

In an optional embodiment, before contacting with the purified organic silica gel adhesive filler, the method further includes: fixing the conductive tape on the hard substrate.

In alternative embodiments, the rigid substrate comprises a glass slide, a rigid aluminum sheet, or a rigid plastic sheet.

In an optional embodiment, in the process of preparing the sample B, the material used to seal the sample A is epoxy resin.

In an optional embodiment, after the solid-sealing, the solid-sealed sample is ground and polished along the direction perpendicular to the bonding surface of the conductive adhesive, so as to obtain a metallographic section exposing the cross-section of the filler particles.

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

In an optional embodiment, scanning electron microscope and energy dispersive spectrometer are used to detect and analyze the morphology, structure size and element distribution of filler particles; and/or X-ray diffractometer is used to analyze the material of representative filler particles. Phase composition was detected and analyzed.

In an optional embodiment, according to GB/T17359-2012 for quantitative analysis of microbeam analysis by energy spectrometry and GB/T16594-2008 for scanning electron microscopy with micron lengths, the morphology, structure size, elements of filler particles distribution was analyzed.

In an optional embodiment, the phase composition of representative filler particles is detected and analyzed according to the general rules of JY/T 0587-2020 polycrystalline X-ray diffraction method.

The beneficial effects of this application include:

The method provided in this application can effectively avoid the interference of silicone components on the identification effect by sequentially purifying, sample preparation, and testing and analyzing the silicone adhesive filler to be identified, and realizes the identification of the filler from the surface and cross-section dimensions, and quickly obtains accurate identification results.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the structural representation of A sample in embodiment 1;

Fig. 2 is the structural representation of B sample in embodiment 1;

Figure 3 is a graph of the Mapping result of the identified product when the filler is not purified in Test Example 1;

Figure 4 is a graph of the Mapping results of the reference product when the filler is not purified in Test Example 1;

Fig. 5 is the Mapping result diagram of the identified product after the filler is purified in Test Example 1;

Fig. 6 is the Mapping result diagram of the reference product after the filler is purified in Test Example 1;

Fig. 7 is a representative scanning electron microscope image of the section of the aluminum-silver-plated filler in Test Example 2;

FIG. 8 is another representative scanning electron microscope of the cross section of the aluminum silver-plated filler in Test Example 2. FIG.

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

Detailed ways

In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

The identification method of the silicone adhesive filler provided in the present application will be specifically described below.

The present application proposes a method for identifying an organic silica gel adhesive filler, which includes the following steps: purifying the organic silica gel adhesive filler to be identified;

The partially purified silicone adhesive filler was attached to the surface of the conductive adhesive to obtain sample A; the remaining part of the purified silicone adhesive filler was made into sample A and then solid-sealed to make a metallographic section exposing the cross section of the filler particle. get B sample;

The filler components in sample A and sample B were analyzed and identified.

In the above process, the purification includes: centrifuging the uncured silicone adhesive containing the filler to be identified, collecting the sediment, and removing the silicone in the sediment.

For reference, the centrifugation can be carried out at least 5min under the condition of not less than 4000r/min to ensure that the filler particles are sufficiently precipitated.

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

The centrifugation time can be 5min, 6min, 7min, 8min, 9min, 10min, 12min, 15min, 20min, 25min or 30min, etc., and can also be other time exceeding 5min.

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

For reference, removing the organosilicon in the precipitate may include: dissolving the organosilicon in the precipitate, solid-liquid separation, and drying the solid phase to obtain an organosilicon adhesive filler without organosilicon.

Wherein, the solvent for dissolving the organosilicon in the precipitate may exemplarily include at least one of petroleum ether, n-hexane, cyclohexane, dichloromethane and benzene.

Preferably, the above-mentioned solvent of at least 10 times the volume of the precipitate (such as 10 times, 12 times, 15 times or 20 times, etc.) is added to the centrifuge tube containing the precipitate to fully dissolve the organic particles in the silicone adhesive. molecular.

In some embodiments, the above-mentioned solid-liquid separation can also be performed by centrifugation. The centrifugation speed is also preferably not less than 4000r/min, and the centrifugation time is preferably not less than 5min.

In a preferred embodiment, the above process of adding a solvent to the precipitate, mixing, and solid-liquid separation to collect the solid phase is repeated to ensure that the precipitate does not contain organosilicon. Exemplarily, the number of repetitions may be 1, 2 or more, depending on the situation of residual silicone in the precipitate.

In the present application, the removal of the organosilicon in the precipitate is based on the fact that the characteristic absorption peak of organosilicon is not observed in the infrared absorption spectrum of the solid phase as the end point.

Specifically, the judgment index of the end point is: under the detection conditions meeting the general rules of GB/T 6040-2019 infrared spectroscopy analysis methods, the absorbance of the absorption peak between 1000cm ^-1 and 1100cm ^-1 in the spectrum is less than 0.05.

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

Further, drying the solid phase can be carried out in a vacuum environment of 45-60° C. for 24-48 hours. Specifically, the precipitate can be spread in a clean petri dish and dried under the above conditions to ensure that the precipitate is fully dried and dispersed and avoid the agglomeration of filler particles.

By purifying the silicone adhesive filler to be identified, so that the filler is separated from the silicone adhesive, the interference of silicone components on the identification effect can be effectively avoided, the difficulty of later analysis and identification is reduced, and the accuracy of identification results is improved.

In the present application, the preparation of sample A includes: contacting the purified silicone adhesive filler with the adhesive surface of the conductive tape used for scanning electron microscope test, and removing unfixed filler particles.

Before contacting with the purified silicone adhesive filler, the method further includes: fixing the conductive tape on the rigid substrate. Rigid substrates may illustratively include glass slides, rigid aluminum sheets, or rigid plastic sheets.

The above-mentioned hard base material has a certain strength, and is not easily deformed and damaged. By fixing the conductive tape on the hard base material, the conductive adhesive can be prevented from being deformed greatly, causing the filler particles fixed thereon to fall off.

In some specific embodiments, the preparation of sample A can refer to the following methods: intercept the conductive tape used in the scanning electron microscope test, fix one side of the conductive tape on the hard substrate, and lift off the protective layer on the other side to make it The viscous adhesive surface is exposed, and then placed in an airtight container containing the purified silicone adhesive filler powder, and the airtight container is shaken to make the adhesive surface of the conductive adhesive fully contact with the purified silicone adhesive filler , after taking it out, purge 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 A Sample.

It should be noted that, by making the filler form a loose thin layer structure on the surface of the conductive adhesive, it can avoid the interference caused by the accumulation of filler particles on the identification effect, and at the same time make the filler cover the entire surface of the conductive adhesive tape. Filler particles can easily be found at the interface of the conductive tape and epoxy.

During the preparation of sample B in the present application, the material used to seal sample A can be exemplarily epoxy resin.

After solid-sealing, the solid-sealed sample is ground and polished along the direction perpendicular to the bonding surface of the conductive adhesive to obtain a metallographic section exposing the cross-section of the filler particles, and the sample obtained at this time is the B sample.

Further, the filler components in samples A and B were analyzed and identified by specific analysis methods.

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

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

Preferably, the morphology, structure size and element distribution of filler particles are detected according to the quantitative analysis of energy spectrometry in microbeam analysis in GB/T 17359-2012 and the scanning electron microscope method of micron length in GB/T 16594-2008. analyze. According to the general rules of JY/T 0587-2020 polycrystalline X-ray diffraction method, the phase composition of representative filler particles was detected and analyzed. to ensure the reliability of the identification results.

On the basis of the above, the identification method provided in this application can effectively avoid the interference of silicone components on the identification effect, realize the identification of fillers from two dimensions of surface and cross-section, and obtain size, morphology, structure, element distribution and phase composition. This information is used to identify fillers to obtain accurate identification results.

The features and performances of the present invention will be further described in detail below in conjunction with the embodiments.

Example 1

The present embodiment provides a method for identifying an organic silica gel adhesive filler, comprising the following steps:

S1. First, separate and purify the uncured organic silica gel adhesive containing the filler through a specific purification process to obtain the purified organic silica gel adhesive filler.

Specifically: centrifuge the uncured silicone adhesive containing the filler (centrifugation speed is 5000r/min, centrifugation time is 10min), collect the sediment in a centrifuge tube, and add 15 times the volume of petroleum to the centrifuge tube ether, after fully mixing, centrifuge the mixed solution (5000r/min, 10min) and collect the solid phase, repeat the above process of adding petroleum ether to the precipitate, mixing well, and centrifuging to collect the solid phase until the GB/ Under the detection conditions of the general rule of T 6040-2019 infrared spectral analysis method, the absorbance of the absorption peak between 1000cm ^-1 and 1100cm ^-1 in the infrared absorption spectrum of the solid phase is less than 0.05. The final precipitate was spread in a clean petri dish, placed in a vacuum environment at 45°C for 24 hours, and dried to obtain a purified silicone adhesive filler.

S2. Prepare sample A and sample B through a specific sample preparation process.

Specifically: cut off the conductive adhesive tape 2 used in the scanning electron microscope test, fix one side of the tape on the hard substrate 3 (glass slide), and peel off the protective layer on the other side to make it have a sticky adhesive surface After exposure, put it into a closed container containing the purified silicone adhesive filler powder, shake the closed container, and make the viscous adhesive surface of the conductive adhesive 2 fully contact with the purified silicone adhesive filler. The surface of the conductive adhesive 2 is purged with a clean nitrogen stream 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 2 is obtained. The sample obtained at this time is sample A (As shown in Figure 1); another A sample is sealed with epoxy resin 4, ground and polished along the direction perpendicular to the bonding surface of conductive adhesive 2, and metallographic sections are made to expose the cross-section of filler particles 1 out to get the B sample (as shown in Figure 2).

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

Specifically: First, according to the relevant requirements of GB/T17359-2012 Microbeam Analysis Energy Spectrometry Quantitative Analysis and GB/T 16594-2008 General Principles of Scanning Electron Microscopy Methods with Micron Length, Scanning Electron Microscope and Energy Spectrometer are used to analyze samples A and B. The samples were analyzed to obtain the morphology, structure size, element distribution and other information of the filler particles 1, and the representative filler particles 1 were selected for X-ray diffractometer detection; According to the relevant requirements of the general principles of diffraction methods, X-ray diffractometer was used to analyze the representative filler particles 1, and the phase composition information of the filler was obtained; finally, the filler of the silicone adhesive was identified by combining this information.

Example 2

The difference between this embodiment and Embodiment 1 is that the centrifugal rotation speed is 4000 r/min, and the centrifugal time is 5 min.

Example 3

The difference between this example and Example 1 is that the solvent is a mixture of n-hexane and cyclohexane at a ratio of 1:1.

Example 4

The difference between this example and Example 1 is that the solvent is dichloromethane.

Example 5

The difference between this example and Example 1 is that the solvent is benzene.

Example 6

The difference between this example and Example 1 is that the amount of solvent is 10 times the volume of the precipitate.

Example 7

The difference between this embodiment and Embodiment 1 is that the hard base material 3 is a hard aluminum sheet.

Example 8

The difference between this embodiment and Embodiment 1 is that the rigid substrate 3 is a rigid plastic sheet.

Test Example 1

Select a certain silicone adhesive with alumina microspheres as a reference product, replace half of the alumina microsphere fillers of the above-mentioned silicone adhesive with silica microspheres in the laboratory, and obtain "adulterated" according to the same process. Silicone adhesive as an identifier.

The filler was not purified, and the comparison results of the Mapping (a working method of scanning electron microscope and energy dispersive spectrometer, which can reflect the distribution of different elements) between the identified product and the reference product are shown in Figure 3 and Figure 4; after purification of the filler , the comparison results of Mapping between the discriminant and the reference product are shown in Figure 5 and Figure 6.

Figures 3 and 4 correspond to the Mapping results of the discriminator and the reference, respectively, in which the elements close to gray and white represent silicon, and those close to black represent aluminum.

From the comparison of Figure 3 and Figure 4, it can be seen that when the filler is not purified, there is no significant difference in the Mapping results of the discriminator and the reference product, and the "adulterated" silica microspheres cannot be visually and clearly identified.

Similarly, Figures 5 and 6 correspond to the Mapping results of the discriminator and the reference, respectively, where the elements close to gray and white represent silicon, and those close to black represent aluminum.

It can be seen from the comparison of Figure 5 and Figure 6 that after the filler is purified, the Mapping results of the discriminator and the reference substance are significantly different, and the "adulterated" silica microspheres can be easily and clearly identified.

Test Example 2

A certain filler is an aluminum-silvered silicone adhesive, and sample B is prepared according to the method provided in Example 1. The representative pictures under the scanning electron microscope are shown in Figures 7 and 8. The results show that: the sample can be clearly The coating structure of the filler is identified, specifically, the coating is a silver-plated layer 5, and its interior corresponds to the aluminum 6 inside the filler.

In summary, the method provided in this application can effectively avoid the interference of silicone components on the identification effect, realize the identification of fillers from two dimensions of surface and cross-section, and obtain size, morphology, structure, element distribution and phase composition, etc. A variety of information for identifying fillers to quickly obtain accurate identification results.

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 changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. an identification method of an organic silica gel adhesive filler, is characterized in that, comprises the following steps: the organic silica gel adhesive filler to be identified is purified; The partially purified silicone adhesive filler was attached to the surface of the conductive adhesive to obtain sample A; the remaining part of the purified silicone adhesive filler was made into sample A and then solid-sealed to make a metallographic section exposing the cross section of the filler particle. get B sample; The filler components in the A sample and the B sample are analyzed and identified respectively. 2. The identification method according to claim 1, wherein the purifying comprises: centrifuging the uncured silicone adhesive containing the filler to be identified, collecting sediment, and removing the silicone in the sediment; Preferably, removing the organosilicon in the precipitate includes: dissolving the organosilicon in the precipitate, solid-liquid separation, and drying the solid phase to obtain an organosilicon adhesive filler without organosilicon. 3. identification method according to claim 2 is characterized in that, centrifugation is to carry out at least 5min under the condition of not less than 4000r/min; Preferably, the centrifugation is performed under the condition of 4000-6000 r/min for 5-10 min. 4. identification method according to claim 2 is characterized in that, the solvent that is used to dissolve the organosilicon in described precipitate comprises at least one in petroleum ether, normal hexane, cyclohexane, methylene dichloride and benzene ; Preferably, the volume of the solvent used for dissolution is at least 10 times the volume of the precipitate. 5. identification method according to claim 2 is characterized in that, removing the organosilicon in the described precipitate is an end point with the characteristic absorption peak of organosilicon not being observed in the infrared absorption spectrum of the solid phase; Preferably, the judgment index of the end point is: under the detection conditions meeting the general rules of GB/T 6040-2019 infrared spectroscopy analysis methods, the absorbance of the absorption peak between 1000cm ^-1 and 1100cm ^-1 in the spectrum is less than 0.05. 6 . The identification method according to claim 2 , wherein the drying of the solid phase is carried out in a vacuum environment of 45-60° C. for 24-48 hours. 7 . 7. The identification method according to claim 1, wherein the preparation of the A sample comprises: contacting the purified silicone adhesive filler with the adhesive surface of the conductive tape used for scanning electron microscopy testing, removing the cemented filler particles; Preferably, the purified silicone adhesive filler forms a loose thin layer structure on the bonding surface of the conductive tape; Preferably, before contacting with the purified organic silica gel adhesive filler, the method further comprises: fixing the conductive tape on the hard substrate; Preferably, the rigid substrate comprises a glass slide, a rigid aluminum sheet or a rigid plastic sheet. 8. The identification method according to claim 7, characterized in that, in the process of preparing the sample B, the material used to seal the sample A is epoxy resin; Preferably, after the solid-sealing, the solid-sealed sample is ground and polished along the direction perpendicular to the bonding surface of the conductive adhesive, so as to obtain a metallographic section exposing the cross-section of the filler particles. 9 . The identification method according to claim 1 , wherein the content of the analysis and identification of the filler components includes at least one of the morphology, structure size, element distribution and phase composition of the filler particles. 10 . 10. The identification method according to claim 9, characterized in that, the morphology, structure size and element distribution of the filler particles are detected and analyzed using a scanning electron microscope and an energy spectrometer; The phase composition of representative filler particles is detected and analyzed; Preferably, the morphology, structure size and element distribution of filler particles are detected and analyzed according to the quantitative analysis of energy spectrometry in microbeam analysis in GB/T17359-2012 and the scanning electron microscope method of micron length in GB/T 16594-2008. ; Preferably, the phase composition of the representative filler particles is detected and analyzed according to the general rules of JY/T 0587-2020 polycrystalline X-ray diffraction method.

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