Black conductive silver paste for automobile glass and preparation method thereof

Abstract

The application discloses a black conductive silver paste for automobile glass and a preparation method thereof, and belongs to the technical field of electronic paste. The components of the conductive silver paste are LSCO conductive ceramic powder, flaky silver powder, glass powder, inorganic additives and an organic carrier. The LSCO conductive ceramic powder is formed by high-temperature sintering of lanthanum oxide, strontium carbonate and cobalt oxide. The glass powder is composed of low-softening-point borosilicate glass powder and high-softening-point borosilicate glass powder. The softening points of the low-softening-point borosilicate glass and the high-softening-point borosilicate glass differ by 100 DEG C to 150 DEG C. The inorganic additives are transition group oxides. The organic carrier comprises a bonding resin and an organic solvent. The preparation method comprises an LSCO conductive ceramic powder preparation method, a glass powder preparation method and a conductive silver paste preparation method. The application solves the problem that the color, adhesion and electrical properties of the existing silver paste after sintering on a glass substrate are difficult to be considered simultaneously. The application can be widely applied in the technical field of simultaneously considering the appearance and electrical properties of automobile windshields.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic paste, further to the technical field of conductive silver paste, in particular to a black conductive silver paste for automobile glass and a preparation method thereof. BACKGROUND

[0002] With the popularity of automobiles in Chinese families, the Chinese automobile industry has grown rapidly, and new automobile products have emerged rapidly. People have also raised new requirements for the quality of automobiles. As the most eye-catching defogging heating line and antenna on the windshield of the car, the brownish yellow produced by the sintering of conductive silver paste and glass tin surface is already incompatible with the beautiful appearance of various types of cars.

[0003] The paste for automobile glass is mainly printed on the rear windshield as a heating defrosting line and a communication antenna. The silver paste for automobile glass not only needs to meet the automobile glass tempering conditions (650℃±50℃ / 200s sintering and rapid cooling after bending), but also needs to meet the long-term exposure to the atmosphere and various detergents under the use conditions of the automobile. Therefore, the silver paste for automobile glass not only needs to be sintered at low temperature and fast, but also has high requirements in terms of temperature impact resistance (matching the thermal expansion coefficient of glass and black glass glaze), strong adhesion to the substrate, oxidation resistance, organic solvent resistance, wear resistance, etc.

[0004] The silver paste for automobile glass is brown yellow after sintering, which has been puzzling the related electronic paste manufacturers, and they have been trying to change the sintering color of silver paste by adding inorganic pigments. In CN113539545A “Gray conductive silver paste for automobile glass and preparation method thereof” disclosed by Shanghai Baoyin Electronic Materials Co., Ltd., a gray silver paste with good conductivity, strong adhesion and good sintering matching with glass substrate is prepared by using flaky silver powder, spherical silver powder, lead-free glass powder, molybdenum trioxide and organic carrier. In US5296413A “Automotive glass thick film conductor paste” disclosed by DuPont, silver powder, two kinds of glass powder with a softening point difference of 100℃, and transition metal oxides (dimanganese trioxide, manganese dioxide, trichromium tetroxide, vanadium pentoxide, etc.) are used as colorants to prepare a paste for automobile glass, and the silver paste is dark brown on the glass tin surface after sintering. In US4728781A “Heated backlights” disclosed by PPG Industries, silver powder, silicate glass powder and silver ion reducing agent (chromium trioxide, stannous sulfate) are used to prepare a silver paste for automobile glass, and the silver ion in the silver paste is reduced by trivalent chromium ion or divalent tin ion during the sintering process, and the reduced silver is aggregated and wrapped by glass to form a silver colloid which can absorb visible light, so that the silver paste is dark gray or black after sintering. FERRO US6624104 uses a weak glass phase containing bismuth to prepare a glass enamel paste, and DKS US5350718 uses zinc sulfide to prepare a glass enamel paste to block the diffusion of silver paste in the glass enamel paste, but this glass system has no effect on the silver paste for automobile glass. When the silver paste is sintered on the glass substrate, silver ions are prone to diffuse into the glass substrate, resulting in coloration of the glass substrate, with the glass air surface being yellow and the glass tin surface being dark yellow or dark brown. The transition metal oxide pigments used in the above patents can improve the color of the paste, but silver ions diffuse into the glass substrate, and the dark color of the paste cannot mask the color of the glass substrate. The use of silver ion reducing agents and sulfides in the silver paste can reduce the diffusion of silver ions into the glass substrate, but too much addition will affect the conductivity and weldability of the silver paste, and the color of the substrate after sintering of the paste does not change much.

[0005] Therefore, the present application is proposed. SUMMARY

[0006] The technical problem to be solved by the present application is to solve the problem that the use of transition metal oxide pigments in the prior art cannot mask the color of the glass substrate, and the use of silver ion reducing agents and sulfides in the silver paste can reduce the diffusion of silver ions into the glass substrate, but affects the conductivity and weldability of the silver paste and the color of the substrate does not change much.

[0007] The application concept of the application is: using LSCO (lanthanum strontium cobalt oxide ceramic) conductive ceramic powder to replace most of the silver powder, transition metal oxide as a silver ion reducing agent, reducing the diffusion of silver ions to the glass substrate during sintering, avoiding the coloring of silver ions on the glass substrate, and the LSCO ceramic powder is black, so that the contact interface between the silver paste and the glass substrate after sintering is black, and the appearance of the windshield is improved.

[0008] The silver paste for automobile glass is prepared by using flaky silver powder and LSCO ceramic powder as conductive phase, borosilicate glass powder with a difference of 150 DEG C between two different softening points as adhesive phase, transition metal oxide Cr2O3 as inorganic additive, and 20% ethyl cellulose solution of menthol as organic carrier, through three-roll mill grinding and dispersion. The conductive layer and the glass substrate combined interface after sintering of the paste is black, and the conductivity, adhesion, sintering matching with the substrate, oxidation resistance, organic solvent resistance and wear resistance can meet the requirements of automobile glass.

[0009] Therefore, the application provides a black conductive silver paste for automobile glass. The components of the conductive paste are as follows in mass percentage:

[0010] LSCO conductive ceramic powder 40% to 70%, flaky silver powder 10% to 30%, glass powder 1% to 5%, inorganic additive 0.2% to 1%, and organic carrier 30% to 50%.

[0011] The LSCO conductive ceramic powder is combined by lanthanum oxide, strontium carbonate and cobalt oxide at high temperature. The components of the LSCO conductive ceramic are as follows in mass percentage: lanthanum oxide 30% to 50%, strontium carbonate 15% to 40%, and cobalt oxide 25% to 30%. The average particle size of the LSCO conductive ceramic powder is 1.0 μm to 5.0 μm, and D90 is less than or equal to 10 μm.

[0012] The particle size of the flaky silver powder is 1.0 μm to 10.0 μm, the specific surface area is 1 m 2 / g to 2 m 2 / g, the loose bulk density is 2 g / ml to 3 g / ml, and the tap density is 3 g / ml to 4 g / ml.

[0013] The glass powder is composed of low softening point borosilicate glass powder and high softening point borosilicate glass powder, and the components in percentage by mass are as follows: the proportion of low softening point glass is 30% to 80%, preferably not more than 50%, because the low softening point glass has low acid resistance, and too high proportion will affect the acid resistance of the conductive layer; the proportion of high softening point glass is 20% to 70%. The softening points of low softening point borosilicate glass and high softening point borosilicate glass differ by 100℃ to 150℃. The softening point of low softening point glass is 400℃ to 520℃, and the softening point of high softening point glass is 550℃ to 650℃. The composition of the low softening point glass is bismuth oxide 60% to 75%, boron oxide 10% to 30%, zinc oxide 5% to 20%, silicon oxide 5% to 10%, aluminum oxide 3% to 10%, and alkali metal oxide <5%; the composition of the high softening point glass is bismuth oxide 50% to 65%, boron oxide 10% to 30%, zinc oxide 5% to 20%, silicon oxide 5% to 15%, aluminum oxide 5% to 15%, antimony pentoxide 5% to 15%, and alkali metal oxide <3%, the alkali metal oxide can be replaced by alkali metal carbonate such as potassium carbonate, sodium carbonate, and the like, preferably sodium carbonate. The glass is ball milled to 1.0μm to 5.0μm after high temperature melting and water quenching, and dried for standby.

[0014] The inorganic additive is a transition group oxide, including one or more oxides of manganese dioxide, cobalt dioxide, vanadium pentoxide, chromium dioxide, and the like, preferably chromium dioxide. The particle size of the inorganic additive is 1.0μm to 5.0μm.

[0015] The organic carrier includes a bonding resin and an organic solvent, the bonding resin includes ethyl cellulose, acrylic resin, polyvinyl butyral, and their derivatives, which can be used alone or in combination according to the film forming condition of the slurry, preferably ethyl cellulose; the organic solvent includes one or more of butyl carbitol, butyl carbitol acetate, and terpineol, preferably terpineol.

[0016] The preparation method of the black conductive silver paste for automobile glass is as follows:

[0017] (1) LSCO conductive ceramic powder preparation method:

[0018] 1) Mixing of raw materials, using yttrium stabilized zirconium ball mill tank, yttrium stabilized zirconium grinding ball, and water as grinding medium, the ball to material to water ratio is 3:1:1 to 5:1:1, mixing for 12h to 48h, and then drying.

[0019] 2) Raw material pre-sintering, using alumina crucible with cover to load the raw materials, preventing excessive volatilization of zinc oxide during sintering, pre-sintering temperature is 1000℃ to 1200℃, and holding time is 1h to 4h.

[0020] 3) Secondary ball milling, using yttrium stabilized zirconium oxide milling tank, yttrium stabilized zirconium oxide grinding ball, water as grinding medium, ball to material to water ratio is 3:1:1~5:1:1, grinding to powder average particle size of 1.0μm~5.0μm, then drying.

[0021] 4) Ceramic sintering, using PVA granulation for the secondary ball-milled powder, using a tablet press to press the powder into a compact block of green body according to the sintering conditions, the green body is sintered by degassing, the sintering temperature is 1200℃~1400℃, and the holding time is 1h~4h.

[0022] 5) Breaking and grinding, using yttrium stabilized zirconium oxide milling tank, yttrium stabilized zirconium oxide grinding ball, water as grinding medium, ball to material to water ratio is 3:1:1~5:1:1, grinding to powder average particle size of 1.0μm~5.0μm, D90≤10μm, then drying for standby.

[0023] (2) Glass powder preparation method:

[0024] According to the requirements of the glass powder components, the raw materials are prepared, mixed to form glass, then high-temperature smelting, water quenching, ball milling to 1.0μm~5.0μm, and drying for standby.

[0025] (3) Preparation method of conductive silver paste:

[0026] According to the component requirements of the conductive silver paste, the conductive ceramic powder, flaky silver powder, glass powder, inorganic additives and organic carrier are proportionally loaded into a stirring device to make the components fully mixed and uniform; a three-roll mill is used to fully grind and disperse the uniformly mixed paste; after the completed paste is filtered to remove impurities, the conductive silver paste for automotive glass is prepared.

[0027] The interface between the sintered conductive layer of the silver paste and the glass substrate is black, and the conductive performance is good, the adhesion to the substrate is strong, and the performance in temperature shock resistance (matching the thermal expansion coefficient of glass and black glass glaze), oxidation resistance, organic solvent resistance, wear resistance, etc. is excellent, which can meet the high reliability requirements of automotive glass. It can be widely used on automotive windshields as a conductor for defrosting, defogging and communication antennas, and can meet the requirements of various types of automotive appearance. DETAILED DESCRIPTION

[0028] The black conductive silver paste for automotive glass and its preparation method are described below with the conductive silver paste for automotive glass as an example.

[0029] Case 1:

[0030] (1) Preparation of LSCO conductive ceramic powder

[0031] According to Table 1:

[0032] Table 1 LSCO conductive ceramic powder formulation table

[0033]

[0034] 1) According to the formulation of Table 1, weigh the raw materials according to the total mass of 1 kg. Mix the raw materials, 3 kg of φ10 mm zirconium oxide grinding balls, and 1 L of water in a 5 L zirconium oxide ball mill tank for 24 hours, and then dry.

[0035] 2) Powder pre-burning, load the material in 1) into an alumina crucible and use a box furnace to sinter, the heating rate is 100 ℃ / h, the sintering temperature is 1050 ℃, the holding time is 3.5 h, and after sintering, the furnace is cooled.

[0036] 3) Secondary ball milling, use a rubber hammer to knock the pre-sintered blocky powder into small pieces, load 3 kg of φ10 mm zirconium oxide grinding balls and 1 L of water into a 5 L zirconium oxide ball mill tank for 48 hours, and then dry.

[0037] 4) Granulation and compaction, use 10% PVA aqueous solution for granulation, the PVA solution ratio is 15% of the powder, and the granulated ceramic powder is pressed into a block-shaped green body using a tablet press at 20 MPa / 15 s.

[0038] 5) Ceramic powder firing, the green body is sintered using a box furnace, the glue removal curve is 100 ℃ / h to 600 ℃, holding for 6 h to complete glue removal, 300 ℃ / h to 1250 ℃, holding time is 3 h, and after sintering, the furnace is cooled.

[0039] 6) Crushing and grinding, the sintered ceramic body is crushed into a large particle powder below 100 μm using a crusher, 3 kg of φ10 mm zirconium oxide grinding balls and 1 L of water are loaded into a 5 L zirconium oxide ball mill tank for 48 h±12 h, and the average particle size of the powder is controlled to be 2 μm-3 μm.

[0040] (2) Glass powder preparation

[0041] According to the formulation in Table 2:

[0042] Table 2 Glass powder formulation table

[0043]

[0044] (3) Organic carrier preparation, the resin in the organic carrier uses ethyl cellulose, and the organic solvent uses a mixture of pine oil and butyl carbitol in a ratio of 1:1. Use a stirring and heating reaction kettle to heat and dissolve the ethyl cellulose, butyl carbitol and pine oil until it is transparent. The dissolved organic carrier is filtered using a filter to remove impurities and undissolved substances for standby.

[0045] (4) Requirements for flaky silver powder, the parameters of flaky silver powder meet the particle size of 1.0 μm-10.0 μm, and the specific surface area is 1 m2 / g~2m 2 / g, the loose bulk density is 2g / ml~3g / ml, and the tap density is 3g / ml~4g / ml.

[0046] (5) Preparation of the conductive silver paste

[0047] According to the formulation in Table 3, the raw materials are weighed according to the total mass of 1kg, evenly dispersed in a stirring device, and then rolled into a conductive silver paste for automobile glass by using a three-roll mill, with the fineness of the paste controlled to be <10μm and the viscosity controlled to be 20Pa•s~60Pa•s.

[0048] Table 3 Formulation table of the conductive silver paste

[0049]

[0050] According to the formulation in Table 3, the raw materials are weighed according to the total mass of 1kg, evenly dispersed in a stirring device, and then rolled into a conductive silver paste for automobile glass by using a three-roll mill, with the fineness of the paste controlled to be <10μm and the viscosity controlled to be 20Pa•s~60Pa•s.

[0051] Case 2:

[0052] (1) Preparation of the conductive silver paste

[0053] According to the formulation in Table 4, the raw materials are weighed according to the total mass of 1kg, evenly dispersed in a stirring device, and then rolled into a conductive silver paste for automobile glass by using a three-roll mill, with the fineness of the paste controlled to be <10μm and the viscosity controlled to be 20Pa•s~60Pa•s.

[0054] Table 4 Formulation table of the conductive silver paste

[0055]

[0056] According to the formulation in Table 4, the raw materials are weighed according to the total mass of 1kg, evenly dispersed in a stirring device, and then rolled into a conductive silver paste for automobile glass by using a three-roll mill, with the fineness of the paste controlled to be <10μm and the viscosity controlled to be 20Pa•s~60Pa•s.

[0057] Case 3:

[0058] (1) Preparation of the conductive silver paste

[0059] According to the formulation in Table 5, the raw materials are weighed according to the total mass of 1kg, evenly dispersed in a stirring device, and then rolled into a conductive silver paste for automobile glass by using a three-roll mill, with the fineness of the paste controlled to be <10μm and the viscosity controlled to be 20Pa•s~60Pa•s.

[0060] Table 5 Formulation table of the conductive silver paste

[0061]

[0062] According to the formulation in Table 5, the raw materials are weighed according to the total mass of 1kg, evenly dispersed in a stirring device, and then rolled into a conductive silver paste for automobile glass by using a three-roll mill, with the fineness of the paste controlled to be <10μm and the viscosity controlled to be 20Pa•s~60Pa•s.

[0063] Comparison of the sintering properties of the silver paste in Case 1~Case 3:

[0064] According to the design of the pattern, the conductive silver paste for automobile glass is printed on the automobile glass, and after drying, a chain furnace is used for sintering, the peak temperature is 620 DEG C, and the holding time is 200s. The performance test of the conductive silver paste after sintering is shown in Table 6.

[0065] Table 6 Performance test table of conductive silver paste for automobile glass

[0066]

[0067] In summary, the conductive silver paste prepared by the technical scheme of the present application is a black sintered conductive paste for automobile glass heating defrosting and signal transmission antenna, and has excellent performance.

[0068] Finally, it should be noted that: the above examples are only examples for clearly illustrating, the present application includes but is not limited to the above examples, here does not need and cannot exhaust all the implementation ways. For those skilled in the art, on the basis of the above description, other different forms of changes or changes can also be made. Any implementation scheme meeting the requirements of the present application belongs to the protection scope of the present application.

Claims

1. A black conductive silver paste for automotive glass, characterized by, The components of the conductive paste are, by mass percentage: LSCO conductive ceramic powder 40%-70%, flaky silver powder 10%-30%, glass powder 1%-5%, inorganic additive 0.2%-1%, and organic carrier 30%-50%; The LSCO conductive ceramic powder is made of lanthanum oxide, strontium carbonate, and cobalt oxide, and the components of the LSCO conductive ceramic are, by mass percentage: lanthanum oxide 30%-50%, strontium carbonate 15%-40%, and cobalt oxide 25%-30%; the average particle size of the LSCO conductive ceramic powder is 1.0 μm-5.0 μm, and D90≤10 μm; The flaky silver powder has a particle size of 1.0-10.0 μm, a specific surface area of 1-2 m 2 / g, a loose bulk density of 2-3 g / ml, and a tap density of 3-4 g / ml. 2 / g, a loose bulk density of 2-3 g / ml, and a tap density of 3-4 g / ml. The glass powder is composed of low-softening-point borosilicate glass powder and high-softening-point borosilicate glass powder, and the components are, by mass percentage: low-softening-point glass 30%-80% and high-softening-point glass 20%-70%; the softening points of the low-softening-point borosilicate glass and the high-softening-point borosilicate glass differ by 100 ℃-150 ℃; The low-softening-point glass is composed of bismuth oxide 60%-75%, boron oxide 10%-30%, zinc oxide 5%-20%, silicon oxide 5%-10%, aluminum oxide 3%-10%, and alkali metal oxide <5%; The high-softening-point glass is composed of bismuth oxide 50%-65%, boron oxide 10%-30%, zinc oxide 5%-20%, silicon oxide 5%-15%, aluminum oxide 5%-15%, antimony pentoxide 5%-15%, and alkali metal oxide <3%; the glass is ball milled to 1.0 μm-5.0 μm after high-temperature smelting and water quenching; The inorganic additive is a transition group oxide, which is composed of one or more oxides of manganese dioxide, cobalt sesquioxide, vanadium pentoxide, and chromium sesquioxide; the particle size of the inorganic additive is 1.0 μm-5.0 μm; The organic carrier includes a bonding resin and an organic solvent, and the bonding resin includes ethyl cellulose, acrylic resin, polyvinyl butyral, or derivatives of ethyl cellulose, acrylic resin, and polyvinyl butyral, which are used alone or in combination according to the film forming condition of the paste; the organic solvent includes one or more of butyl carbitol, butyl carbitol acetate, and terpineol.

2. The black conductive silver paste for automotive glass according to claim 1, characterized in that: The proportion of the low-softening-point glass is not more than 50%.

3. The black conductive silver paste for automotive glass according to claim 1, wherein the black conductive silver paste is used for a black conductive layer of an automotive glass. The softening point of the low-softening-point glass is 400 ℃-520 ℃, and the softening point of the high-softening-point glass is 550 ℃-650 ℃.

4. The black conductive silver paste for automotive glass according to claim 1, wherein: The alkali metal oxide is an alkali metal carbonate, and the alkali metal carbonate is potassium carbonate or sodium carbonate.

5. The method for preparing a black conductive silver paste for automotive glass as described in claim 1, characterized in that, The preparation method is: (1) LSCO conductive ceramic powder preparation method: 1) mixing raw materials, using a yttrium-stabilized zirconia ball mill tank, yttrium-stabilized zirconia grinding balls, and water as the grinding medium, the ball-to-material-to-water ratio is 3:1:1-5:1:1, and the mixture is dried after mixing for 12 h-48 h; 2) raw material pre-sintering, using an alumina crucible with a cover to hold the raw materials to prevent excessive volatilization of zinc oxide during sintering, the pre-sintering temperature is 1000 ℃-1200 ℃, and the holding time is 1 h-4 h; 3) Secondary ball milling, using yttrium stabilized zirconium oxide milling tank, yttrium stabilized zirconium oxide grinding ball, water as grinding medium, ball material water ratio is 3:1:1~5:1:1, grinding to powder average particle size is 1.0μm~5.0μm after drying; 4) Ceramic sintering, using PVA granulation of secondary ball milling powder, according to the sintering conditions using tablet press to press the powder into compact block green body, green body through the glue sintering, sintering temperature is 1200℃~1400℃, holding time is 1h~4h; 5) Broken grinding, using yttrium stabilized zirconium oxide milling tank, yttrium stabilized zirconium oxide grinding ball, water as grinding medium, ball material water ratio is 3:1:1~5:1:1, grinding to powder average particle size is 1.0μm~5.0μm, D90≤10μm after drying for standby; (2) Glass powder preparation method: According to the glass powder component requirements, the raw materials are prepared, mixed to make glass, and then ball milled to 1.0μm~5.0μm after high temperature smelting and water quenching, dried for standby; (3) Conductive silver paste preparation method: According to the component requirements of the conductive silver paste, the conductive ceramic powder, flaky silver powder, glass powder, inorganic additives and organic carrier are proportionally loaded into the stirring equipment to make the components fully mixed and uniform; the mixed and uniform paste is fully ground and dispersed by using three roll mill; The prepared paste is filtered to remove impurities, thereby preparing the conductive silver paste for automobile glass.

6. The black conductive silver paste for automobile glass according to claim 1, characterized in that: (1) The formula of the LSCO conductive ceramic powder is: La2O3 41.3%, SrCO3 24.3% and Co3O4 34.4%; (2) The formula of the glass powder is: Low softening point glass powder: Bi2O3 65.70%, SiO2 6.57%, Al2O3 4.52%, ZnO 10.40%, B2O3 8.62% and Na2CO3 4.20%; High softening point glass powder: Bi2O3 52.4%, SiO2 8.03%, Al2O3 6.13%, Sb2O5 7.64%, ZnO 10.31%, B2O3 13.52% and Na2CO3 1.97%.

7. The method of claim 6, wherein the black conductive silver paste for an automotive glass is prepared by adding 0.1 to 0.5 parts by weight of the black pigment to 100 parts by weight of the silver powder, and mixing the black pigment and the silver powder. The specific method is: (1) LSCO conductive ceramic powder preparation 1) According to the formula of the LSCO conductive ceramic powder, the raw materials are weighed according to the total mass of 1kg, and then the raw materials, 3kg φ10mm zirconium oxide grinding ball and 1L water are loaded into a 5L zirconium oxide ball mill tank for mixing for 24 hours and then dried; 2) Powder pre-sintering, the material in 1) is loaded into an alumina crucible and sintered using a box furnace, the heating rate is 100℃ / h, the sintering temperature is 1050℃, and the holding time is 3.5h, and then the sintered product is cooled in the furnace; 3) Secondary ball milling, the pre-sintered blocky powder is knocked into small pieces using a rubber hammer, 3kg φ10mm zirconium oxide grinding ball and 1L water are loaded into a 5L zirconium oxide ball mill tank for mixing for 48 hours and then dried; 4) Granulation and briquetting, using 10% PVA aqueous solution for granulation, the PVA solution ratio is 15% of the powder, and the granulated ceramic powder is pressed into blocky green body using a tablet press at 20MPa / 15s. 5) porcelain powder firing, green body using box furnace sintering, the glue discharge curve is 100℃ / h to 600℃, holding 6h to complete the glue discharge, 300℃ / h to 1250℃, holding time 3h, after sintering, cooling with the furnace; 6) crushing and grinding, the porcelain body after firing is crushed into 100μm or less large particle powder, 3kg φ10mm zirconium oxide grinding balls and 1L water are loaded into a 5L zirconium oxide ball mill tank for mixing for 48h±12h, and the average particle size of the powder is controlled to be 2μm~3μm; (2) Glass powder preparation 1) According to the formula of the glass powder, the raw materials are weighed; 2) Glass melting, peak temperature 1300℃, holding 1h, after sintering, water quenching; 3) Glass powder grinding, using zirconium oxide tank and zirconium oxide grinding balls, the glass powder is ground to an average particle size of 2μm~3μm; (3) Organic carrier preparation The resin in the organic carrier uses ethyl cellulose, and the organic solvent uses a mixture of terpineol and butyl carbitol, with a ratio of 1:1; an agitated heating reaction kettle is used to heat and dissolve the ethyl cellulose, butyl carbitol and terpineol until they are transparent; the organic carrier after dissolution is filtered using a filter to remove impurities and undissolved substances, and is ready for use; (4) The flaky silver powder has a particle size of 1.0-10.0 μm, a specific surface area of 1-2 m 2 / g, a loose bulk density of 2-3 g / ml, and a tap density of 3-4 g / ml. 2 / g, a loose bulk density of 2-3 g / ml, and a tap density of 3-4 g / ml. (5) Preparation of conductive silver paste The formula of the conductive silver paste is: LSCO powder 45%, flaky silver powder 15%, low softening point glass powder 1%, high softening point glass powder 3%, chromium trioxide 0.5%, and organic carrier 35.5%; The raw materials are weighed according to the total mass of 1kg, uniformly dispersed in a stirring device, and then rolled into conductive silver paste for automobile glass using a three-roll mill, with the fineness of the paste controlled to be <10μm and the viscosity controlled to be 20Pa•s~60Pa•s.

8. The method of claim 7, wherein the black conductive silver paste for an automotive glass is prepared by adding 0.1 to 0.5 parts by weight of the black pigment to 100 parts by weight of the silver powder, and mixing the black pigment and the silver powder. The formula of the conductive silver paste is: LSCO powder 52.5%, flaky silver powder 17.5%, low softening point glass powder 1.2%, high softening point glass powder 3.5%, chromium trioxide 0.58%, and organic carrier 24.72%.

9. The method for preparing a black conductive silver paste for automotive glass as described in claim 7, characterized in that, The formula of the conductive silver paste is: LSCO powder 60%, flaky silver powder 20%, low softening point glass powder 1.7%, high softening point glass powder 3.0%, chromium trioxide 0.58%, and organic carrier 14.72%.

10. The black conductive silver paste for automotive glass according to claim 1, wherein the black conductive silver paste is used for a black conductive layer of an automotive glass. The conductive silver paste is printed on the automobile glass, dried, and then sintered using a chain furnace, with a peak temperature of 620℃ and a holding time of 200s; after sintering, the adhesion of the conductive silver film is ≥20N, the color is black, and the square resistance is 8 mΩ / □~15 mΩ / □.

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