Nondestructive identification method and nondestructive identification system device for dispersing agent on surface of silver powder

Abstract

The invention provides a lossless identification method and a lossless identification system device for a dispersing agent on the surface of silver powder. The lossless identification method comprises the following steps: (1) heating the silver powder, pre-vacuumizing, backfilling protective gas, vacuumizing, and cooling the pre-vacuumizing and the vacuumized gas at the same time; and (2) performing gas chromatography and mass spectrometry test on the cooled substance to identify the dispersing agent on the surface of the silver powder. According to the lossless identification method, stripping of the dispersing agent on the surface of the silver powder can be achieved at the low temperature, other reagents do not need to be introduced, the dispersing agent is in a low-activity state and is basically in the atmosphere of protective gas, cross reaction and decomposition can be eradicated, the dispersing agent structure on the surface of the silver powder is lossless, and the detection accuracy is high. The real condition that the subsequently detected substance reacts with the dispersing agent is ensured; and the experiment steps are simple, safe and easy to operate.

Description

Technical Field

[0001] The invention belongs to the technical field of testing, and relates to a nondestructive identification method and a nondestructive identification system device for a silver powder surface dispersant. Background Art

[0002] At present, the photovoltaic industry is booming, and the photovoltaic silver paste industry is growing rapidly. As one of the most important raw materials for photovoltaic silver paste, silver powder is the key research and development target in this industry. Since silver powder accounts for nearly 90% of the mass proportion in photovoltaic silver paste electrode materials, the compatibility and interaction mechanism between silver powder, glass powder and organic carrier have important practical and theoretical guiding significance for the preparation of silver paste.

[0003] The coating and analysis of the dispersant (also called coating agent in the industry) on the surface of silver powder has always been the focus of attention. At present, there are two main methods used in the industry, solvent extraction and thermal cracking. As mentioned in patent CN106573300B, the surface treatment agent is subjected to solvent extraction and measured using a carbon automatic analyzer or GC-MS; or, the dispersant detached from the surface of the silver powder by heating using a pyrolyzer or the like is measured using a carbon automatic analyzer or GC-MS.

[0004] The steps of the solvent extraction method are as follows: add 1 mL of a mixture of hydrochloric acid and methanol (hydrogen chloride-methanol reagent manufactured by Tokyo Chemical Industry Co., Ltd.) to 0.5 g of silver powder, and heat it at 50°C for 30 minutes to remove the organic matter from the surface of the silver powder and methylate the functional groups. After cooling, add 1 mL of pure water and 2 mL of n-hexane and shake to extract the methylated organic matter into the hexane layer. By analyzing the composition of the hexane layer using the above-mentioned GC-MS, the organic matter on the surface of the silver powder was identified.

[0005] The solvent extraction method uses a mixture of hydrochloric acid and methanol, and also involves experimental steps such as esterification reaction and extraction separation. The mixture of hydrochloric acid and methanol is a reagent that dissolves hydrogen chloride gas in methanol. The storage condition of the solution is 2-8°C. The solution has poor stability and requires special protection during transportation, storage and use, which brings safety risks to the laboratory. In addition, the experimental steps of the solvent extraction method are cumbersome. Under the current situation of increasingly stringent laboratory safety regulations, the storage and use of such hazardous sources in the laboratory are not only cumbersome, but also pose safety hazards.

[0006] In addition, the thermal cracking method is to use a pyrolyzer to heat the silver powder at high temperature to separate the organic matter from the surface of the silver powder, and then use GC-MS to identify the above-mentioned organic matter. The thermal cracking method requires expensive thermal cracking equipment with a high market price. The experiment is generally carried out under high temperature conditions of 300°C or even higher. The stripped organic matter is prone to further reaction or self-decomposition, and the fragments after decomposition may reassemble, and it cannot be guaranteed that the detected fragments can truly reflect the situation of the dispersant.

[0007] Therefore, there is an urgent need to provide a non-destructive identification method for the dispersant on the surface of silver powder, which does not require the introduction of reagents and can be processed at a lower temperature, and can ensure the true situation of the material reaction dispersant detected subsequently. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a non-destructive identification method and a non-destructive identification system device for the dispersant on the surface of silver powder. The non-destructive identification method of the present invention can realize the stripping of the dispersant on the surface of silver powder at a relatively low temperature without the introduction of other reagents. The dispersant is in a low-activity state and is basically in an atmosphere of protective gas, which can prevent cross-reaction and decomposition, making the dispersant structure on the surface of the silver powder intact, ensuring that the substances detected subsequently reflect the true situation of the dispersant; and the experimental steps are simple, safe and easy to operate; there is no need to configure expensive thermal cracking equipment, and there is no risk of distortion of the dispersant after cracking and reorganization.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a non-destructive identification method for a silver powder surface dispersant, the non-destructive identification method comprising:

[0011] (1) heating the silver powder, pre-vacuuming, backfilling with protective gas, and then vacuuming, while cooling the pre-vacuuming and vacuuming gases;

[0012] (2) The cooled substance is subjected to gas chromatography-mass spectrometry testing to identify the dispersant on the surface of the silver powder.

[0013] It should be noted that the surface of the silver powder in step (1) contains a dispersant, which includes but is not limited to saturated fatty acids, oleic acid, ricinoleic acid and laconic acid.

[0014] In the present invention, during the pre-vacuuming, backfilling with protective gas and vacuuming steps in step (1), the silver powder is always in a heated state; the vacuuming and heating steps are stopped together.

[0015] Optionally, after the vacuuming and heating steps are stopped together, protective gas is filled in to maintain air pressure balance.

[0016] The present invention provides a non-destructive identification method for a dispersant on the surface of silver powder, which can realize the stripping of the dispersant on the surface of the silver powder at a relatively low temperature without introducing other reagents. The dispersant is in a low-activity state and is basically in an atmosphere of protective gas, which can prevent cross-reaction and decomposition, and make the dispersant structure on the surface of the silver powder intact, thereby ensuring that the substance detected subsequently reflects the true situation of the dispersant. In addition, the experimental steps are simple, safe and easy to operate; there is no need to configure expensive thermal cracking equipment additionally, and there is no risk of distortion of the dispersant due to recombination after cracking.

[0017] Preferably, the silver powder includes silver powder for photovoltaic silver paste. The surface of the silver powder for photovoltaic silver paste generally contains a dispersant, and the dispersant may be at least one of lauric acid, palmitic acid, stearic acid and ricinoleic acid.

[0018] Preferably, the heating temperature is 80-120°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, etc.

[0019] In the present invention, the dispersant on the surface of the silver powder can be stripped at a relatively low temperature, i.e., 80-120°C.

[0020] Preferably, the pressure after the pre-vacuuming is -0.1 to -0.05 Pa, for example, it may be -0.1 Pa, -0.09 Pa, -0.08 Pa, -0.07 Pa, -0.06 Pa or -0.05 Pa.

[0021] Preferably, the pre-vacuuming time is 0.5-1 h, for example, 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h or 1 h.

[0022] Preferably, the protective gas includes at least one of nitrogen, argon and helium.

[0023] In the present invention, after the protective gas is backfilled, the gas pressure returns to normal pressure.

[0024] Preferably, the pressure after vacuuming is -0.1 to -0.05 Pa, for example, it may be -0.1 Pa, -0.09 Pa, -0.08 Pa, -0.07 Pa, -0.06 Pa or -0.05 Pa.

[0025] Preferably, the vacuuming time is 0.5-1 h, for example, 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h or 1 h.

[0026] Preferably, in step (1), the steps of backfilling the protective gas and evacuating the air are repeated at least twice, for example, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times or 10 times, etc., preferably 3-6 times.

[0027] Preferably, the cooling method includes a room temperature water bath or an ice water bath.

[0028] Preferably, in the gas chromatography-mass spectrometry test, the temperature increase program of the gas chromatography includes:

[0029] The temperature is raised to a preset temperature (e.g., 280°C) at a heating rate of 10-20°C / min (e.g., 10°C / min, 12°C / min, 14°C / min, 16°C / min, 18°C / min, or 20°C / min, etc.), and kept warm for 5-10 min (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min, etc.).

[0030] Preferably, in the gas chromatography-mass spectrometry test, the starting temperature of the gas chromatography is 50-100°C, for example, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C.

[0031] Preferably, in the gas chromatography-mass spectrometry test, the starting temperature is maintained for 3 minutes and then the temperature is increased.

[0032] Preferably, in the gas chromatography-mass spectrometry test, the temperature increase program of the gas chromatography specifically includes:

[0033] The starting temperature of the gas chromatography was 50-100°C, which was kept at 50-100°C for 3 min, then heated to 280°C at a heating rate of 10-20°C / min and kept for 5-10 min.

[0034] Preferably, in the gas chromatography-mass spectrometry test, the helium flow rate of the gas chromatography is 0.5-3 mL / min, for example, it can be 0.5 mL / min, 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min or 3 mL / min.

[0035] Preferably, in the gas chromatography-mass spectrometry test, the ion source used in the mass spectrometry is an electron impact source (EI), preferably a positive EI.

[0036] Preferably, the electron energy of the electron bombardment source is 70.0 eV.

[0037] Preferably, the temperature of the positron bombardment source is 230°C.

[0038] Preferably, in the gas chromatography-mass spectrometry test, the quadrupole temperature used in the mass spectrometry is 150°C.

[0039] Preferably, in the gas chromatography-mass spectrometry test, the collection mode of the mass analyzer used in the mass spectrometry is the ion collection mode (SIM).

[0040] Preferably, the scanning range of the ion collection mode is 50-550 m / z.

[0041] As a preferred technical solution of the present invention, the non-destructive identification method specifically includes:

[0042] (I) heating silver powder for photovoltaic silver paste, pre-evacuating, then backfilling with protective gas, and then evacuating; the steps of backfilling with protective gas and evacuating are repeated 3-6 times; and the gas extracted by the pre-evacuation and the evacuation is cooled at the same time;

[0043] (II) dissolving the cooled substance with a chromatographically pure reagent, and conducting a gas chromatography-mass spectrometry test to identify the dispersant on the surface of the silver powder;

[0044] Wherein, the chromatographically pure reagent includes at least one of methanol, ethyl acetate, acetonitrile, tetrahydrofuran and N,N-dimethylformamide (DMF).

[0045] In the present invention, during the pre-vacuuming, backfilling with protective gas and vacuuming steps in step (I), the silver powder is always in a heated state; the last vacuuming step is completed together with the heating.

[0046] Optionally, after the vacuuming and heating steps are completed together, a protective gas is filled in to maintain the gas pressure balance.

[0047] In a second aspect, the present invention provides a non-destructive identification system device for a silver powder surface dispersant, the non-destructive identification system device comprising a heating container, a vacuum pumping component, a collecting device, and a gas chromatography-mass spectrometry device;

[0048] The heating container is used to heat the silver powder and is connected to a protective gas source; the collecting device includes a collecting container and a cooling element, the cooling element is used to cool the material in the collecting container, and the rear end of the collecting container is provided with the vacuum pumping assembly;

[0049] The gas chromatography-mass spectrometry device is used for performing gas chromatography-mass spectrometry testing on the substances in the collection container.

[0050] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0051] The system refers to an equipment system, a device system or a production device.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention provides a non-destructive identification method for a dispersant on the surface of silver powder, which can realize the stripping of the dispersant on the surface of the silver powder at a relatively low temperature without introducing other reagents. The dispersant is in a low-activity state and is basically in an atmosphere of protective gas, which can prevent cross-reaction and decomposition, and make the dispersant structure on the surface of the silver powder intact, thereby ensuring that the substance detected subsequently reflects the true situation of the dispersant. In addition, the experimental steps are simple, safe and easy to operate; there is no need to configure expensive thermal cracking equipment additionally, and there is no risk of distortion of the dispersant due to recombination after cracking. DETAILED DESCRIPTION

[0054] It should be understood that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0055] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0056] In one embodiment, the present invention provides a non-destructive identification system device for a silver powder surface dispersant, the non-destructive identification system device comprising a heating container, a vacuum pumping component, a collecting device, and a gas chromatography-mass spectrometry device;

[0057] The heating container is a flask, which is used to carry and heat silver powder; the collecting device includes a collecting container and a cooling element, and the cooling element includes a cooling container, and a cooling medium is contained in the cooling container; a vacuum pumping component is provided at the tail end of the collecting container, and part of the collecting container is located in the cooling medium, which can cool the material drawn into the collecting container; the heating container is also connected to a protective gas source;

[0058] The gas chromatography-mass spectrometry device is used for performing gas chromatography-mass spectrometry testing on the substances in the collection container.

[0059] Example 1

[0060] This embodiment provides a method for non-destructively identifying a dispersant on the surface of silver powder using the device of the above embodiment, comprising the following steps:

[0061] (1) Silver powder (denoted as SV01) is placed in a flask and heated to 80°C. At this temperature, vacuum is evacuated until the pressure gauge indicates -0.05 Pa, pre-vacuuming for 0.5 h, and then backfilled with nitrogen until the pressure gauge indicates the normal pressure in the laboratory, and then vacuumed again until the pressure gauge indicates -0.05 Pa, maintaining this vacuum for 0.5 h. At the same time, all gases extracted by pre-vacuuming and vacuuming are cooled with normal temperature water; after the steps of backfilling with nitrogen and vacuuming are repeated 3 times, heating and vacuuming are stopped, and nitrogen is filled into the system device;

[0062] (2) Use chromatographically pure methanol to dissolve the dispersant condensed and attached to the collection container, transfer it into a sample bottle, and prepare it for gas chromatography and mass spectrometry (GC-MS) testing; the gas chromatography conditions of GC-MS are as follows: the column oven is heated by a programmed temperature increase method, the starting temperature of the temperature increase program is 50°C, the starting temperature holding time is 3 minutes, the heating rate is 10°C / min, the final temperature is 280°C, the final temperature holding time is 5 minutes, and the helium flow rate is 0.5 mL / min; the mass spectrometry conditions are as follows: the ion source is an electron impact source (positive EI), the electron energy is 70.0 eV, the ion source temperature is 230°C, the quadrupole temperature is 150°C, the mass analyzer acquisition mode selects the ion acquisition mode (SIM), and the scanning range is 50-550 m / z.

[0063] Example 2

[0064] This embodiment provides a method for non-destructively identifying a dispersant on the surface of silver powder using the device of the above embodiment, comprising the following steps:

[0065] (1) silver powder (denoted as SV02) is placed in a flask and heated to 120°C. At this temperature, vacuum is evacuated to a pressure gauge indicating -0.07 Pa, pre-vacuuming for 1 hour, and then backfilled with nitrogen until the pressure gauge indicates the normal pressure in the laboratory, and then vacuumed again to a pressure gauge indicating -0.07 Pa, maintaining this vacuum for 1 hour, and at the same time, all gases extracted by pre-vacuuming and vacuuming are cooled with an ice-water mixture; after the steps of backfilling with nitrogen and vacuuming are cycled 6 times, heating and vacuuming are stopped, and helium is filled into the system device;

[0066] (2) Use chromatographically pure acetonitrile to dissolve the dispersant condensed and attached to the collection container, transfer it into a sample bottle, and prepare it for gas chromatography and mass spectrometry (GC-MS) testing; the gas chromatography conditions of GC-MS are as follows: the column oven is heated by a programmed temperature increase method, the starting temperature of the temperature increase program is 80°C, the starting temperature holding time is 3 minutes, the heating rate is 15°C / min, the final temperature is 280°C, the final temperature holding time is 10 minutes, and the helium flow rate is 3 mL / min; the mass spectrometry conditions are as follows: the ion source is an electron impact source (positive EI), the electron energy is 70.0 eV, the ion source temperature is 230°C, the quadrupole temperature is 150°C, the mass analyzer acquisition mode selects the ion acquisition mode (SIM), and the scanning range is 50-550 m / z.

[0067] Example 3

[0068] This embodiment provides a method for non-destructively identifying a dispersant on the surface of silver powder using the device of the above embodiment, comprising the following steps:

[0069] (1) silver powder (denoted as SV03) is placed in a flask and heated to 110°C. At this temperature, vacuum is evacuated until the pressure gauge indicates -0.1 Pa, pre-vacuuming for 0.8 h, and then backfilled with nitrogen until the pressure gauge indicates the normal pressure in the laboratory, and then vacuumed again until the pressure gauge indicates -0.1 Pa, maintaining this vacuum for 0.8 h, and at the same time, all gases extracted by pre-vacuuming and vacuuming are cooled with an ice-water mixture; after the steps of backfilling with nitrogen and vacuuming are repeated 5 times, heating and vacuuming are stopped, and nitrogen is filled into the system device;

[0070] (2) Use chromatographically pure tetrahydrofuran (THF) to dissolve the dispersant condensed and attached to the collection container, transfer it into a sample bottle, and prepare it for gas chromatography and mass spectrometry (GC-MS) testing; the gas chromatography conditions of GC-MS are as follows: the column oven is heated by a programmed temperature increase method, the starting temperature of the temperature increase program is 70°C, the starting temperature holding time is 3 minutes, the heating rate is 15°C / min, the final temperature is 280°C, the final temperature holding time is 5 minutes, and the helium flow rate is 1.5 mL / min; the mass spectrometry conditions are as follows: the ion source is an electron impact source (positive EI), the electron energy is 70.0 eV, the ion source temperature is 230°C, the quadrupole temperature is 150°C, the mass analyzer acquisition mode selects the ion acquisition mode (SIM), and the scanning range is 50-550 m / z.

[0071] Example 4

[0072] This embodiment provides a method for non-destructively identifying a dispersant on the surface of silver powder using the device of the above embodiment, comprising the following steps:

[0073] (1) silver powder (denoted as SV04) is placed in a flask and heated to 95°C. At this temperature, vacuum is evacuated until the pressure gauge indicates -0.05 Pa, pre-vacuum for 0.5 h, and then nitrogen is backfilled until the pressure gauge indicates the normal pressure in the laboratory, and then vacuum is evacuated again until the pressure gauge indicates -0.05 Pa, and this vacuum is maintained for 0.5 h. At the same time, all gases extracted by pre-vacuuming and vacuuming are cooled with normal temperature water; after the steps of backfilling nitrogen and vacuuming are repeated 3 times, heating and vacuuming are stopped, and argon is filled into the system device;

[0074] (2) Use chromatographically pure tetrahydrofuran (THF) to dissolve the dispersant condensed and attached to the collection container, transfer it into a sample bottle, and prepare it for gas chromatography and mass spectrometry (GC-MS) testing; the gas chromatography conditions of GC-MS are as follows: the column oven is heated by a programmed temperature increase method, the starting temperature of the temperature increase program is 80°C, the starting temperature holding time is 3 minutes, the heating rate is 13°C / min, the final temperature is 280°C, the final temperature holding time is 8 minutes, and the helium flow rate is 1.0 mL / min; the mass spectrometry conditions are as follows: the ion source is an electron impact source (positive EI), the electron energy is 70.0 eV, the ion source temperature is 230°C, the quadrupole temperature is 150°C, the mass analyzer acquisition mode selects the ion acquisition mode (SIM), and the scanning range is 50-550 m / z.

[0075] Example 5

[0076] This embodiment provides a method for non-destructively identifying a dispersant on the surface of silver powder using the device of the above embodiment, comprising the following steps:

[0077] (1) Silver powder (denoted as SV05) is placed in a flask and heated to 100°C. At this temperature, vacuum is evacuated until the pressure gauge indicates -0.08 Pa, pre-vacuuming for 0.5 h, and then backfilled with nitrogen until the pressure gauge indicates the normal pressure in the laboratory, and then vacuumed until the pressure gauge indicates -0.08 Pa, maintaining this vacuum for 0.5 h, and at the same time, all gases extracted by pre-vacuuming and vacuuming are cooled with an ice-water mixture; after the steps of backfilling with nitrogen and vacuuming are repeated 3 times, heating and vacuuming are stopped, and nitrogen is filled into the system device;

[0078] (2) Use chromatographically pure methanol to dissolve the dispersant condensed and attached to the collection container, transfer it into a sample bottle, and prepare it for gas chromatography and mass spectrometry (GC-MS) testing; the gas chromatography conditions of GC-MS are as follows: the column oven is heated by a programmed temperature increase method, the starting temperature of the temperature increase program is 50°C, the starting temperature holding time is 3 minutes, the heating rate is 18°C / min, the final temperature is 280°C, the final temperature holding time is 10 minutes, and the helium flow rate is 0.5 mL / min; the mass spectrometry conditions are as follows: the ion source is an electron impact source (positive EI), the electron energy is 70.0 eV, the ion source temperature is 230°C, the quadrupole temperature is 150°C, the mass analyzer acquisition mode selects the ion acquisition mode (SIM), and the scanning range is 50-550 m / z.

[0079] Example 6

[0080] The only difference between this embodiment and embodiment 1 is that the heating temperature is adjusted to 75°C.

[0081] Example 7

[0082] The only difference between this embodiment and embodiment 1 is that the heating temperature is adjusted to 125°C.

[0083] Comparative Example 1

[0084] This comparative example provides a method for identifying a dispersant on the surface of silver powder, comprising:

[0085] Weigh about 5g of the silver powder SV01 in Example 1, add 10mL of hydrochloric acid methanol solution, heat treat for 30min in a water bath at 50°C, cool to room temperature, and take out the organic layer; add 10mL of pure water and 20mL of n-hexane to the above organic layer, extract and shake for 1min, then let it stand for 10min, after 3 cycles, let it stand for more than 2h, and the methylated organic matter is extracted into the n-hexane layer; take the organic layer, add about 10g of anhydrous Na2SO4 thereto, dry the organic layer, and let it stand overnight; take the dried organic layer, dilute it with 2.5 times n-hexane, put it into a GC-MS sample bottle, and run the GC-MS test, using the same GC-MS test conditions and parameters as Example 1.

[0086] Comparative Example 2

[0087] This comparative example provides a method for identifying a dispersant on the surface of silver powder, comprising:

[0088] The silver powder SV02 in Example 2 was subjected to high-temperature exfoliation using a thermal pyrolysis injector, the pyrolysis temperature being 280° C. After exfoliation, the sample was directly injected for testing, and the same GC-MS test conditions and parameters as in Example 2 were used.

[0089] Comparative Example 3

[0090] This comparative example provides a method for identifying a dispersant on the surface of silver powder, comprising:

[0091] The silver powder SV03 in Example 3 was subjected to high-temperature exfoliation using a thermal pyrolysis injector, the pyrolysis temperature being 360° C. After exfoliation, the sample was directly injected for testing, and the same GC-MS test conditions and parameters as those in Example 3 were used.

[0092] Comparative Example 4

[0093] This comparative example provides a method for identifying a dispersant on the surface of silver powder, comprising:

[0094] Weigh about 5g of the silver powder SV04 in Example 4, add 10mL of hydrochloric acid methanol solution, heat treat for 30min in a water bath at 50°C, cool to room temperature, and take out the organic layer; add 10mL of pure water and 20mL of n-hexane to the above organic layer, extract and shake for 1min, then let it stand for 10min, cycle 3 times, let it stand for more than 2h, and extract the methylated organic matter into the n-hexane layer; take the organic layer, add about 10g of anhydrous Na2SO4 thereto, dry the organic layer, and let it stand overnight; take the dried organic layer, dilute it with 2.5 times n-hexane, put it into a GC-MS sample bottle, and run the GC-MS test using the same GCMS test conditions and parameters as Example 4.

[0095] Comparative Example 5

[0096] This comparative example provides a method for identifying a dispersant on the surface of silver powder, comprising:

[0097] The silver powder SV05 in Example 5 was subjected to high-temperature exfoliation using a thermal pyrolysis injector at a pyrolysis temperature of 300° C. After exfoliation, the sample was directly injected for testing. The same GC-MS test conditions and parameters as in Example 5 were used.

[0098] The results of the identification of Examples 1-7 and Comparative Examples 1-5 are summarized in Table 1. Among them, the chemical formula of lauric acid is C 12 H 24 O2, the chemical formula of palmitic acid is C 16 H 32 O2, the chemical formula of oleic acid is C 18 H 34 O2, the chemical formula of stearic acid is C 18 H 36 O2, the chemical formula of ricinoleic acid is C 18 H 34 O3.

[0099] Table 1

[0100]

[0101]

[0102] analyze:

[0103] It can be seen from the results of Examples 1-5 and Comparative Examples 1-5 that the method of the present invention is suitable for non-destructive identification of various dispersants on the surface of silver powders, and compared with the traditional solvent extraction method and thermal cracking method, the method of the present invention can accurately identify the type of dispersant without the generation of impurities; while when the solvent extraction method and thermal cracking method are used to identify the dispersant, impurities are easily generated, affecting the authenticity of the results.

[0104] From the results of Example 1 and Examples 6-7, it can be seen that when the heating temperature is between 80°C and 120°C, it is beneficial to the non-destructive identification of the dispersant on the surface of the silver powder. If the heating temperature is lower than 80°C, the dispersant on the surface of the silver powder will not be completely peeled off, resulting in a small amount of dispersant collected and difficult to detect; if the heating temperature is higher than 120°C, the temperature will be high, heating will be inconvenient, and insulation will be required, which is extra consumption and unnecessary.

[0105] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A non-destructive identification method of a silver powder surface dispersant, characterized in that: The non-destructive identification method comprises: (1) heating the silver powder, pre-vacuuming, backfilling with protective gas, and then vacuuming, while cooling the pre-vacuuming and vacuuming gases; (2) The cooled substance is subjected to gas chromatography-mass spectrometry testing to identify the dispersant on the surface of the silver powder.

2. The nondestructive identification method according to claim 1, characterized in that: The silver powder includes silver powder for photovoltaic silver paste.

3. The nondestructive identification method according to claim 1 or 2, characterized in that: The heating temperature is 80-120°C.

4. The non-destructive identification method according to any one of claims 1 to 3, characterized in that: The pressure after the pre-vacuuming is -0.1 to -0.05 Pa; Preferably, the pre-vacuuming time is 0.5-1h.

5. The non-destructive identification method according to any one of claims 1 to 4, characterized in that: The protective gas includes at least one of nitrogen, argon and helium.

6. The non-destructive identification method according to any one of claims 1 to 5, characterized in that: The pressure after vacuuming is -0.1 to -0.05 Pa; Preferably, the vacuuming time is 0.5-1h; Preferably, in step (1), the steps of backfilling the protective gas and evacuating the air are repeated at least 2 times, preferably 3-6 times.

7. The non-destructive identification method according to any one of claims 1 to 6, characterized in that: In the gas chromatography-mass spectrometry test, the temperature increase program of the gas chromatography includes: Heat up to the preset temperature at a heating rate of 10-20℃ / min and keep warm for 5-10min; Preferably, in the gas chromatography-mass spectrometry test, the starting temperature of the gas chromatography is 50-100°C; Preferably, in the gas chromatography-mass spectrometry test, the helium flow rate of the gas chromatography is 0.5-3 mL / min.

8. The non-destructive identification method according to any one of claims 1 to 7, characterized in that: In the gas chromatography-mass spectrometry test, the ion source used in the mass spectrometry is an electron bombardment source; Preferably, in the gas chromatography-mass spectrometry test, the collection mode of the mass analyzer used in the mass spectrometry is an ion collection mode; Preferably, the scanning range of the ion collection mode is 50-550 m / z.

9. The non-destructive identification method according to any one of claims 1 to 8, characterized in that: The non-destructive identification method specifically comprises: (I) heating silver powder for photovoltaic silver paste, pre-evacuating, then backfilling with protective gas, and then evacuating; the steps of backfilling with protective gas and evacuating are repeated 3-6 times; and the gas extracted by the pre-evacuation and the evacuation is cooled at the same time; (II) dissolving the cooled substance with a chromatographically pure reagent, and conducting a gas chromatography-mass spectrometry test to identify the dispersant on the surface of the silver powder; Wherein, the chromatographically pure reagent includes at least one of methanol, ethyl acetate, acetonitrile, tetrahydrofuran and N,N-dimethylformamide.

10. A non-destructive identification system device for silver powder surface dispersant, characterized in that: The nondestructive identification method according to any one of claims 1 to 9 is performed using the nondestructive identification system device; The nondestructive identification system device includes a heating container, a vacuum pumping component, a collecting device, and a gas chromatography-mass spectrometry device; The heating container is used to heat the silver powder and is connected to a protective gas source; the collecting device includes a collecting container and a cooling element, the cooling element is used to cool the material in the collecting container, and the rear end of the collecting container is provided with the vacuum pumping assembly; The gas chromatography-mass spectrometry device is used for performing gas chromatography-mass spectrometry testing on the substances in the collection container.

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