A nondestructive identification method and nondestructive identification system device for silver powder surface dispersants

Abstract

The application provides a nondestructive identification method and nondestructive identification system device for a silver powder surface dispersant, and the nondestructive identification method comprises the following steps: (1) heating silver powder, pre-vacuumizing, backfilling protective gas, vacuumizing again, and cooling the gas extracted by pre-vacuumizing and vacuumizing; (2) performing gas chromatography-mass spectrometry testing on the obtained substance after cooling, so as to identify the silver powder surface dispersant. According to the nondestructive identification method, the silver powder surface dispersant can be stripped at a lower temperature, other reagents do not need to be introduced, the dispersant is in a low-activity state and is basically in the atmosphere of protective gas, cross-reactions and decomposition can be avoided, the structure of the silver powder surface dispersant is nondestructive, the real situation of the dispersant can be ensured, and the subsequent detected substance is reacted, and the experimental steps are simple, safe and easy to operate.

Description

TECHNICAL FIELD

[0001] The application 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

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

[0003] The coating and analysis of the dispersant (also known as the coating agent in the industry) on the surface of the silver powder has always been the focus. Currently, there are two main methods used in the industry: solvent extraction method and thermal cracking method. For example, patent CN106573300B mentions a method of solvent extraction of the surface treatment agent and determination using a carbon automatic analyzer or GC-MS; or a method of determining the dispersant separated from the surface of the silver powder by heating using a thermal decomposer, using a carbon automatic analyzer or GC-MS.

[0004] The steps of the solvent extraction method are as follows: 1 mL of a mixture of hydrochloric acid and methanol (hydrogen chloride-methanol reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.) is added to 0.5 g of silver powder, and heating treatment is carried out at 50°C for 30 minutes, so that the organic matter is separated from the surface of the silver powder, and the functional group is methylated. After cooling, 1 mL of pure water and 2 mL of n-hexane are added and shaken to extract the methylated organic matter into the hexane layer. The composition of the above-mentioned hexane layer is analyzed by using the above-mentioned GC-MS, and the organic matter on the surface of the silver powder is identified.

[0005] The mixture of hydrochloric acid and methanol used in the solvent extraction method also involves esterification reaction, extraction separation and other experimental steps. The mixture of hydrochloric acid and methanol is a reagent in which hydrogen chloride gas is dissolved in methanol. The storage condition of the solution is 2-8°C, and the solution stability is poor. Special protection is required during transportation, storage and use, which brings safety risks to the laboratory. Moreover, the experimental steps of the solvent extraction method are complicated. Under the current situation of more and more strict laboratory safety standards, the storage and use of such dangerous sources in the laboratory not only have complicated procedures, but also have safety hazards.

[0006] In addition, the thermal cracking method is to heat silver powder at high temperature by using a thermal cracker to make organic matters separate from the surface of silver powder, and then use GC-MS to identify the separated organic matters. The thermal cracking method needs expensive thermal cracking equipment, and the market price is high. The experiment is generally carried out at a high temperature of 300 DEG C or even higher. The separated organic matters are easy to further react or crack by themselves. The fragments after cracking may recombine, and it cannot be guaranteed that the detected fragments can truly reflect the situation of the dispersant.

[0007] Therefore, it is urgent to provide a non-destructive identification method of silver powder surface dispersant, which does not need to introduce reagents and can be processed at a lower temperature, and can guarantee that the detected substances truly reflect the situation of the dispersant. SUMMARY

[0008] In view of the deficiencies of the prior art, the purpose of the present application is to provide a non-destructive identification method and system device of silver powder surface dispersant. The non-destructive identification method of the present application can separate the silver powder surface dispersant at a lower temperature, and does not need to introduce other reagents. The dispersant is in a low activity state and is basically in the atmosphere of protective gas. Cross-reaction and decomposition can be prevented, the structure of the dispersant on the surface of the silver powder is not damaged, and it is guaranteed that the detected substances truly reflect the situation of the dispersant. In addition, the experimental steps are simple, safe and easy to operate. No additional expensive thermal cracking equipment is needed, and the dispersant has no risk of distortion after recombination.

[0009] To achieve this purpose, the present application adopts the following technical solutions:

[0010] In a first aspect, the present application provides a non-destructive identification method of silver powder surface dispersant, which comprises:

[0011] (1) heating silver powder, pre-evacuating, backfilling protective gas, vacuumizing, and cooling the gas evacuated in the pre-evacuating and vacuumizing;

[0012] (2) testing the cooled substances by gas chromatography-mass spectrometry to identify the dispersant on the surface of silver powder.

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

[0014] In the present application, the silver powder is always in a heated state during the steps of pre-evacuating, backfilling protective gas and vacuumizing in step (1). The vacuumizing and heating steps are stopped together.

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

[0016] The application provides a non-destructive identification method for a silver powder surface dispersant, which can realize stripping of the silver powder surface dispersant at a low temperature, without introducing other reagents, and the dispersant is in a low activity state and is basically in a protective gas atmosphere, so that cross-reaction and decomposition can be avoided, the structure of the silver powder surface dispersant is not damaged, the real situation of the dispersant is ensured, and subsequent detection is ensured; and the experimental steps are simple, safe and easy to operate; no additional expensive thermal cracking equipment is needed, and the dispersant has no distortion risk after cracking and recombination.

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

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

[0019] In the application, the silver powder surface dispersant can be stripped at a low temperature of 80-120℃.

[0020] Preferably, the pressure after pre-evacuation is-0.1~-0.05Pa, for example, it can be-0.1Pa, -0.09Pa, -0.08Pa, -0.07Pa, -0.06Pa or-0.05Pa, etc.

[0021] Preferably, the pre-evacuation time is 0.5-1h, for example, it can be 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1h, etc.

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

[0023] In the application, after backfilling the protective gas, the gas pressure is restored to normal pressure.

[0024] Preferably, the pressure after evacuation is-0.1~-0.05Pa, for example, it can be-0.1Pa, -0.09Pa, -0.08Pa, -0.07Pa, -0.06Pa or-0.05Pa, etc.

[0025] Preferably, the evacuation time is 0.5-1h, for example, it can be 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1h, etc.

[0026] Preferably, in step (1), the steps of backfilling the protective gas and vacuumizing are repeated at least 2 times, for example, can be 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 normal temperature water bath or an ice water bath.

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

[0029] Rising at a temperature rising rate of 10-20℃ / min (for example, can be 10℃ / min, 12℃ / min, 14℃ / min, 16℃ / min, 18℃ / min or 20℃ / min, etc.) to a preset temperature (for example, can be 280℃), and holding for 5-10 min (for example, can be 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℃, for example, can be 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃, etc.

[0031] Preferably, in the gas chromatography-mass spectrometry test, the holding time at the starting temperature is 3 min, and then rising.

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

[0033] The starting temperature of the gas chromatography is 50-100℃, holding for 3 min at 50-100℃, then rising at a temperature rising rate of 10-20℃ / min to 280℃, and holding 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, can be 0.5 mL / min, 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min or 3 mL / min, etc.

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

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

[0037] Preferably, the temperature of the positive electron impact source is 230℃.

[0038] Preferably, in the gas chromatography-mass spectrometry test, the quadrupole temperature of the mass spectrometer is 150℃.

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

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

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

[0042] (I) heating the silver powder for photovoltaic silver paste, pre-evacuating, backfilling protective gas, and then evacuating; the steps of backfilling protective gas and evacuating are repeated for 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 material with chromatographically pure reagents, and performing gas chromatography-mass spectrometry test to identify the dispersant on the surface of the silver powder;

[0044] The chromatographically pure reagents include at least one of methanol, ethyl acetate, acetonitrile, tetrahydrofuran, and N,N-dimethylformamide (DMF).

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

[0046] Optionally, after the evacuation step is ended together with the heating step, protective gas is filled to maintain the pressure balance.

[0047] In a second aspect, the present application provides a non-destructive identification system device for the dispersant on the surface of silver powder, which comprises a heating container, an evacuation assembly, a collection device, and a gas chromatography-mass spectrometry device.

[0048] The heating container is used for heating the silver powder and is connected with a protective gas source; the collection device comprises a collection container and a cooling member, the cooling member is used for cooling the material in the collection container, and the tail end of the collection container is provided with the evacuation assembly.

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

[0050] The numerical range in the present application not only includes the point values exemplified above, but also includes any point values between the above numerical ranges which are not exemplified; due to the limited space and for the purpose of simplicity, the present application does not list the specific point values included in the range.

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

[0052] Compared with the prior art, the beneficial effects of the present application are:

[0053] The present application provides a non-destructive identification method for silver powder surface dispersant, which can realize the stripping of silver powder surface dispersant at a lower temperature, without introducing other reagents, dispersant in a low activity state, and basically in a protective gas atmosphere, which can prevent cross-reaction and decomposition, so that the structure of the dispersant on the surface of the silver powder is not damaged, and the subsequent detected substance reaction is the true situation of the dispersant; and the experimental steps are simple, safe and easy to operate; without additional configuration of expensive thermal cracking equipment, and the dispersant has no distortion risk after cracking and recombination. DETAILED DESCRIPTION

[0054] It should be understood that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "provided", "connected", "connected" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0055] The technical solutions of the present application are further illustrated by specific embodiments.

[0056] In one embodiment, the present application provides a non-destructive identification system device for silver powder surface dispersant, which comprises a heating container, a vacuum pumping assembly, a collection device and a gas chromatograph and mass spectrometer combination device;

[0057] The heating container is a flask for carrying and heating silver powder; the collection device comprises a collection container and a cooling member, the cooling member comprises a cooling container, and the cooling container contains a cooling medium; the tail end of the collection container is provided with a vacuum pumping assembly, and part of the collection container is located in the cooling medium, so that the substance pumped into the collection container can be cooled; the heating container is also connected with a protective gas source;

[0058] The gas chromatograph and mass spectrometer combination device is used for gas chromatograph and mass spectrometer combination test of the substance in the collection container.

[0059] Example 1

[0060] The present embodiment provides a method for non-destructive identification of silver powder surface dispersant by using the above-mentioned device, comprising the following steps:

[0061] (1) The silver powder (denoted as SV01) was placed in a flask and heated to 80°C. At this temperature, vacuum was extracted to a pressure gauge indicating -0.05 pa, and pre-vacuum was extracted for 0.5 h. Then, nitrogen was backfilled to a pressure gauge indicating normal pressure in the laboratory, and vacuum was extracted again to a pressure gauge indicating -0.05 Pa. The vacuum was maintained for 0.5 h, while all the gases extracted by pre-vacuum and vacuum extraction were cooled by using normal temperature water. After the backfilling of nitrogen and vacuum extraction were repeated for 3 times, heating and vacuum extraction were stopped, and nitrogen was filled into the system device;

[0062] (2) The dispersant condensed and attached to the collection container was dissolved by using chromatographically pure methanol, and was transferred into a sample bottle, ready for GC-MS test. The gas chromatography conditions of GC-MS were as follows: the column oven was heated by using a programmed temperature rising mode, the initial temperature was 50°C, the initial temperature holding time was 3 min, the temperature rising rate was 10°C / min, the final temperature was 280°C, the final temperature holding time was 5 min, and the helium flow rate was 0.5 mL / min. The mass spectrometry conditions were as follows: the ion source was an electron impact source (positive EI), the electron energy was 70.0 eV, the ion source temperature was 230°C, the quadrupole temperature was 150°C, and the mass analyzer collection mode was ion collection mode (SIM) with a scanning range of 50-550 m / z.

[0063] Example 2

[0064] The present embodiment provides a method for nondestructive identification of the dispersant on the surface of silver powder by using the device of the above-mentioned embodiment, which comprises the following steps:

[0065] (1) The silver powder (denoted as SV02) was placed in a flask and heated to 120°C. At this temperature, vacuum was extracted to a pressure gauge indicating -0.07 pa, and pre-vacuum was extracted for 1 h. Then, nitrogen was backfilled to a pressure gauge indicating normal pressure in the laboratory, and vacuum was extracted again to a pressure gauge indicating -0.07 Pa. The vacuum was maintained for 1 h, while all the gases extracted by pre-vacuum and vacuum extraction were cooled by using an ice-water mixture. After the backfilling of nitrogen and vacuum extraction were repeated for 6 times, heating and vacuum extraction were stopped, and helium was filled into the system device;

[0066] (2) Chromatographically pure acetonitrile is used to dissolve the condensed dispersant attached to the collection container, and is transferred into a sample bottle, ready for GC-MS testing; the GC conditions of GC-MS are as follows: the column oven is programmed to increase the temperature, the initial temperature is 80℃, the initial temperature holding time is 3 min, the temperature increasing rate is 15℃ / min, the final temperature is 280℃, the final temperature holding time is 10 min, and the helium flow rate is 3 mL / min; the MS 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℃, the quadrupole temperature is 150℃, the mass analyzer is selected in ion collection mode (SIM), and the scanning range is 50-550 m / z.

[0067] Example 3

[0068] The embodiment provides a method for nondestructively identifying the dispersant on the surface of silver powder by using the device in the above embodiment, and the method comprises the following steps:

[0069] (1) The silver powder (denoted as SV03) is placed in a flask and heated to 110℃, at which temperature, vacuum is extracted until the pressure gauge indicates -0.1 Pa, pre-vacuum is extracted for 0.8 h, then nitrogen is backfilled until the pressure gauge indicates the normal pressure in the laboratory, vacuum is extracted again until the pressure gauge indicates -0.1 Pa, and the vacuum is maintained for 0.8 h, while all the gas extracted by pre-vacuum and vacuum extraction is cooled by an ice-water mixture; after the backfilling of nitrogen and the vacuum extraction are cycled for 5 times, the heating and vacuum extraction are stopped, and nitrogen is filled into the system device;

[0070] (2) Chromatographically pure tetrahydrofuran (THF) is used to dissolve the condensed dispersant attached to the collection container, and is transferred into a sample bottle, ready for GC-MS testing; the GC conditions of GC-MS are as follows: the column oven is programmed to increase the temperature, the initial temperature is 70℃, the initial temperature holding time is 3 min, the temperature increasing rate is 15℃ / min, the final temperature is 280℃, the final temperature holding time is 5 min, and the helium flow rate is 1.5 mL / min; the MS 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℃, the quadrupole temperature is 150℃, the mass analyzer is selected in ion collection mode (SIM), and the scanning range is 50-550 m / z.

[0071] Example 4

[0072] The embodiment provides a method for nondestructively identifying the dispersant on the surface of silver powder by using the device in the above embodiment, and the method comprises the following steps:

[0073] (1) The silver powder (denoted as SV04) was placed in a flask and heated to 95°C. At this temperature, vacuum was extracted to a pressure gauge indicating -0.05 Pa, and pre-vacuum was performed for 0.5 h. Then, nitrogen was backfilled to a pressure gauge indicating normal pressure in the laboratory, and vacuum was extracted again to a pressure gauge indicating -0.05 Pa. This vacuum was maintained for 0.5 h, while all the gases extracted by pre-vacuum and vacuum extraction were cooled using normal temperature water. After the backfilling of nitrogen and vacuum extraction were repeated for 3 times, heating and vacuum extraction were stopped, and argon was filled into the system device;

[0074] (2) The dispersant attached to the collection container was dissolved and condensed using chromatographically pure tetrahydrofuran (THF), and was transferred into a sample bottle, ready for gas chromatography-mass spectrometry (GC-MS) testing. The gas chromatography conditions of GC-MS were as follows: the column oven was heated using a programmed temperature method, the initial temperature was 80°C, the initial temperature was maintained for 3 min, the temperature rising rate was 13°C / min, the final temperature was 280°C, the final temperature was maintained for 8 min, and the helium flow rate was 1.0 mL / min. The mass spectrometry conditions were as follows: the ion source was an electron impact source (positive EI), the electron energy was 70.0 eV, the ion source temperature was 230°C, the quadrupole temperature was 150°C, and the mass analyzer was collected in ion collection mode (SIM) with a scanning range of 50-550 m / z.

[0075] Example 5

[0076] The present embodiment provides a method for non-destructive identification of the surface dispersant of silver powder using the above-mentioned device, comprising the following steps:

[0077] (1) The silver powder (denoted as SV05) was placed in a flask and heated to 100°C. At this temperature, vacuum was extracted to a pressure gauge indicating -0.08 Pa, and pre-vacuum was performed for 0.5 h. Then, nitrogen was backfilled to a pressure gauge indicating normal pressure in the laboratory, and vacuum was extracted again to a pressure gauge indicating -0.08 Pa. This vacuum was maintained for 0.5 h, while all the gases extracted by pre-vacuum and vacuum extraction were cooled using an ice-water mixture. After the backfilling of nitrogen and vacuum extraction were repeated for 3 times, heating and vacuum extraction were stopped, and nitrogen was filled into the system device;

[0078] (2) The dispersant condensed and adhered to the collection container was dissolved with chromatographically pure methanol, transferred into a sample bottle, and prepared for gas chromatography-mass spectrometry (GC-MS) testing. The gas chromatography conditions of GC-MS were as follows: the column oven was heated in a programmed manner, the initial temperature was 50°C, the initial temperature was maintained for 3 min, the temperature rising rate was 18°C / min, the final temperature was 280°C, the final temperature was maintained for 10 min, and the helium flow rate was 0.5 mL / min. The mass spectrometry conditions were as follows: the ion source was an electron impact source (positive EI), the electron energy was 70.0 eV, the ion source temperature was 230°C, the quadrupole temperature was 150°C, the mass analyzer was collected in an ion collection mode (SIM), and the scanning range was 50-550 m / z.

[0079] Example 6

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

[0081] Example 7

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

[0083] Comparative Example 1

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

[0085] About 5 g of silver powder SV01 in Example 1 was weighed, 10 mL of a methanolic hydrochloric acid solution was added, and the mixture was heated in a water bath at 50°C for 30 min. After cooling to room temperature, the organic layer was removed. 10 mL of pure water and 20 mL of n-hexane were added to the above organic layer, and the mixture was shaken for 1 min and then statically placed for 10 min. After 3 cycles, the mixture was statically placed for more than 2 h until the methylated organic matter was extracted into the n-hexane layer. The organic layer was taken, about 10 g of anhydrous Na2SO4 was added, and the organic layer was dried. After static placement overnight, the dried organic layer was diluted with 2.5 times n-hexane, loaded into a GC-MS sample bottle, and subjected to GC-MS testing. The same GC-MS testing conditions and parameters as in Example 1 were used.

[0086] Comparative Example 2

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

[0088] The silver powder SV02 in Example 2 was subjected to high-temperature stripping using a thermal cracking sampler, and the cracking temperature was 280°C. After stripping, the sample was directly tested. The same GC-MS testing conditions and parameters as in Example 2 were used.

[0089] Comparative Example 3

[0090] The present comparative example provides a method for identifying a surface dispersant of silver powder, comprising:

[0091] The silver powder SV03 in Example 3 was pyrolyzed by a thermal pyrolysis sampler, and the pyrolysis temperature was 360°C. After pyrolysis, the sample was directly tested, and the same GC-MS test conditions and parameters as in Example 3 were used.

[0092] Comparative Example 4

[0093] The present comparative example provides a method for identifying a surface dispersant of silver powder, comprising:

[0094] About 5g of silver powder SV04 in Example 4 was weighed, 10mL of methanolic hydrochloric acid solution was added, and the mixture was heated in a water bath at 50°C for 30min. After cooling to room temperature, the organic layer was removed. 10mL of pure water and 20mL of n-hexane were added to the above organic layer, and the mixture was shaken for 1min and then statically placed for 10min. After 3 cycles, the mixture was statically placed for more than 2h, and the methylated organic matter was extracted into the n-hexane layer. The organic layer was taken, about 10g of anhydrous Na2SO4 was added, and the organic layer was dried. After static placement overnight, the dried organic layer was diluted with 2.5 times of n-hexane, loaded into a GC-MS sample bottle, and tested by GC-MS. The same GC-MS test conditions and parameters as in Example 4 were used.

[0095] Comparative Example 5

[0096] The present comparative example provides a method for identifying a surface dispersant of silver powder, comprising:

[0097] The silver powder SV05 in Example 5 was pyrolyzed by a thermal pyrolysis sampler, and the pyrolysis temperature was 300°C. After pyrolysis, the sample was directly tested, and the same GC-MS test conditions and parameters as in Example 5 were used.

[0098] The results identified in Examples 1-7 and Comparative Examples 1-5 are shown 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] Analysis:

[0103] From the results of examples 1-5 and comparative examples 1-5, it can be seen that the method of the present application is suitable for non-destructive identification of various silver powder surface dispersants, and compared with the traditional solvent extraction method and thermal cracking method, the method of the present application can accurately identify the type of dispersant without the generation of impurities; while identifying the dispersant by the solvent extraction method and the thermal cracking method, impurities are easily generated, which affects 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℃ and 120℃, it is beneficial to the non-destructive identification of silver powder surface dispersants. If the heating temperature is lower than 80℃, it will lead to incomplete stripping of the silver powder surface dispersant, so that the amount of collected dispersant is small and it is not easy to detect; if the heating temperature is higher than 120℃, it will lead to high temperature, which is not convenient for heating, and it needs to be insulated, which consumes extra and is unnecessary.

[0105] The applicant declares that the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application, which can be easily thought of by any person skilled in the art, falls within the protection scope and disclosure scope of the present application.

Claims

1. A non-destructive identification method for silver powder surface dispersants, characterized in that, The non-destructive testing method includes: (1) Heat the silver powder and pre-evacuate it, then backfill it with protective gas, and then evacuate it again. At the same time, cool the gas extracted during the pre-evacuation and the vacuuming. (2) The substance obtained by cooling is subjected to gas chromatography and mass spectrometry to identify the dispersant on the surface of the silver powder; The heating temperature is 80-120℃.

2. The non-destructive testing method according to claim 1, characterized in that, The silver powder includes silver powder used in photovoltaic silver paste.

3. The non-destructive testing method according to claim 1, characterized in that, The pressure after pre-vacuuming is .

4. The non-destructive testing method according to claim 1, characterized in that, The pre-vacuuming time is 0.5-1 hour.

5. The non-destructive testing method according to claim 1, characterized in that, The protective gas includes at least one of nitrogen, argon, and helium.

6. The non-destructive testing method according to claim 1, characterized in that, The pressure after vacuuming is .

7. The non-destructive testing method according to claim 1, characterized in that, The vacuuming time is 0.5-1 hour.

8. The non-destructive testing method according to claim 1, characterized in that, In step (1), the steps of backfilling protective gas and evacuating are repeated at least twice.

9. The non-destructive testing method according to claim 8, characterized in that, In step (1), the steps of backfilling protective gas and evacuating are repeated 3-6 times.

10. The non-destructive testing method according to claim 1, characterized in that, In the gas chromatography-mass spectrometry (GC-MS) coupled test, the temperature program for GC includes: Heat to the preset temperature at a rate of 10-20℃ / min and hold for 5-10 minutes.

11. The non-destructive testing method according to claim 1, characterized in that, In the gas chromatography-mass spectrometry (GC-MS) test, the initial temperature of the gas chromatography is 50-100℃.

12. The non-destructive testing method according to claim 1, characterized in that, In the gas chromatography-mass spectrometry (GC-MS) test, the helium flow rate for GC is 0.5-3 mL / min.

13. The non-destructive testing method according to claim 1, characterized in that, In the gas chromatography-mass spectrometry (GC-MS) test, the ion source used for mass spectrometry is an electron impact source.

14. The non-destructive testing method according to claim 1, characterized in that, In the gas chromatography-mass spectrometry (GC-MS) test, the mass spectrometer used the ion acquisition mode.

15. The non-destructive testing method according to claim 14, characterized in that, The scanning range of the ion acquisition mode is 50-550 m / z.

16. The non-destructive testing method according to claim 1, characterized in that, The non-destructive testing method specifically includes: (I) Heat the silver powder in the photovoltaic silver paste and perform pre-vacuuming, then backfill with protective gas and perform vacuuming again; repeat the steps of backfilling with protective gas and vacuuming 3-6 times; at the same time, cool the gas extracted during the pre-vacuuming and vacuuming. (II) Dissolve the substance obtained by cooling using chromatographically pure reagents, and perform gas chromatography and mass spectrometry to identify the dispersant on the surface of the silver powder; The chromatographically pure reagents include at least one of methanol, ethyl acetate, acetonitrile, tetrahydrofuran, and N,N-dimethylformamide; The heating temperature is 80-120℃.

17. A non-destructive testing system for silver powder surface dispersants, characterized in that, The non-destructive testing method according to any one of claims 1-16 is performed using the aforementioned non-destructive testing system device; The non-destructive testing system includes a heating container, a vacuum assembly, a collection device, and a gas chromatography-mass spectrometry (GC-MS) system. 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 component, the cooling component is used to cool the substance in the collecting container, and the vacuum assembly is provided at the tail end of the collecting container. The gas chromatography-mass spectrometry (GC-MS) device is used to perform GC-MS testing on substances in the collection container.

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