A black conductive silver paste for automotive glass and its preparation method

Abstract

The present application relates to a kind of black conductive silver paste for automotive glass and its preparation method, black conductive silver paste includes: metal silver powder 68-88%; Silver nickelate 3-6%; Glass powder 3-7%; High molecular resin 0.5-9%; Organic additive 0.5-2%; Organic solvent 4.5-25%; Preparation method includes: first, high molecular resin and organic solvent are mixed, heated and dissolved, filtration, obtain organic carrier;Again, organic additive is added to organic carrier, mix, again, metal silver powder, silver nickelate, glass powder are added in mixing machine and uniformly mixed and dispersed, obtain uniform black paste;Finally, the black paste is ground in three-roll mill, the fineness of black silver paste is controlled to be below 15 μm, the viscosity is 20-30Pa·S, obtain black conductive silver paste.Compared with prior art, the present application not only can meet the sintering process of existing thickened automotive glass, and black glaze has good matching, under the premise of meeting conductivity, weldability and weldability, it can also well cope with the color requirement of conductive silver paste on automobile in future.

Description

Technical Field

[0001] This invention belongs to the field of conductive silver paste technology, and relates to a black conductive silver paste for automotive glass and its preparation method. Background Technology

[0002] As automotive glass becomes increasingly thicker, higher temperatures are required for tempering. However, during the sintering process of conductive silver paste at 700–720℃, the thicker automotive glass, especially in the busbar area, suffers from poor sintering of the silver paste layer / black enamel layer / glass layer due to the significant heat reflection caused by the silver color. This negatively impacts the overall quality of the vehicle. Therefore, to maintain production costs, some glass manufacturers have higher requirements for silver paste.

[0003] Chinese Patent 201711104822.4 discloses an anti-oxidation silver paste for bus windshields and its preparation method. This technical solution can meet the requirements of existing bus windshields for conductivity, adhesion, tin surface color, and anti-oxidation.

[0004] Chinese Patent 202310879103.9 discloses a conductive silver paste for automotive coated glass and its preparation method, belonging to the field of functional glass technology. This technical solution effectively solves the problems of low resistance, adhesion, wide sintering window, and bonding strength between the silver paste and copper foil.

[0005] However, the aforementioned conductive silver paste still suffers from high sintering temperature, poor weldability, and inadequate sintering of the silver paste layer / black glaze layer / glass layer in actual use, failing to meet the sintering process requirements of modern thickened automotive glass. Summary of the Invention

[0006] The purpose of this invention is to provide a black conductive silver paste for automotive glass and its preparation method. It not only meets the sintering process of existing thickened automotive glass and has good compatibility with black glaze, but also, while satisfying conductivity, weldability and solderability, the tin surface color is very different from the tin surface color of traditional silver pastes, which can well meet the color requirements of conductive silver paste for future automotive applications.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] The first aspect of the present invention provides a black conductive silver paste for automotive glass, comprising the following components and weight percentages: 68-88% metallic silver powder; 3-6% silver nickelate; 3-7% glass powder; 0.5-9% polymer resin; 0.5-2% organic additives; and 4.5-25% organic solvent.

[0009] Furthermore, the metallic silver powder is selected from at least one of silver micro powder 1#, silver micro powder 2#, or silver micro powder 3#;

[0010] The silver micro powder #1 has an average particle size of 2.6 μm, a tap density of 4.1 g / mL, and a loose packing density of 2.2 g / mL.

[0011] The silver micro powder #2 has an average particle size of 2.1 μm, a tap density of 3.2 g / mL, and a loose packing density of 1.4 g / mL.

[0012] The silver micro powder #3 has an average particle size of 1.9 μm, a tap density of 2.8 g / mL, and a loose packing density of 1.3 g / mL.

[0013] Furthermore, the metallic silver powder is a mixture of at least two of silver micro powder 1#, silver micro powder 2#, or silver micro powder 3#.

[0014] Furthermore, the silver nickelate is selected from one of silver nickelate 1#, silver nickelate 2#, or silver nickelate 3#;

[0015] The silver nickelate 1# has a nickel content of 0.1% and a density of 10.5 g·cm³. -3 ;

[0016] The silver nickelate 2# has a nickel content of 10% and a density of 10.1 g·cm³. -3 ;

[0017] The silver nickelate #3 has a nickel content of 15% and a density of 10.2 g·cm³. -3 .

[0018] Furthermore, the glass powder is lead-free glass powder with an average particle size of 1.5-2.5 μm and a coefficient of thermal expansion of 85 × 10⁻⁶. -7 / K, sintering temperature is 540-670℃, including the following components and weight percentages: 28% silicon dioxide, 6% niobium pentoxide, 0.5% ferric oxide, 8% sodium oxide, 13% boron oxide, 9.5% zinc oxide, 3% bismuth oxide, 9% titanium oxide, 1.5% manganese trioxide, 3.5% zirconium oxide, 4% yttrium oxide, 3% aluminum oxide, 3.5% lithium oxide, and 7.5% potassium oxide.

[0019] Furthermore, the polymer resin is ethyl cellulose.

[0020] Furthermore, the organic additive is selected from one of dispersants, plasticizers, or defoamers;

[0021] The dispersant is selected from at least one of Silco Wet D-504 / PEG, BYK-312, or ED120;

[0022] The plasticizer is selected from at least one of dibutyl phthalate (DBP), dibutyl phthalate or trioctyl citrate;

[0023] The defoamer is selected from at least one of BYK-333, BYK-354, TSA-750S, Silco AF 100 or BYK-300.

[0024] Furthermore, the organic solvent is selected from at least one of terpineol, diethylene glycol dibutyl ether, or dipropylene glycol monomethyl ether.

[0025] A second aspect of the present invention provides a method for preparing black conductive silver paste for automotive glass, comprising the following steps:

[0026] S1: Mix the polymer resin and organic solvent, heat to dissolve, filter, and obtain the organic carrier;

[0027] S2: Add organic additives to organic carrier, mix, then add metallic silver powder, silver nickelate and glass powder in a mixer and mix and disperse evenly to obtain a uniform black slurry;

[0028] S3: The black paste is ground in a three-roll mill to control the fineness of the black silver paste to below 15μm and the viscosity to 20-30Pa·S, thus obtaining black conductive silver paste.

[0029] Furthermore, in step S1, the heating and dissolving temperature is 70-80°C, and the sieve used in the filtration is a 300-400 mesh sieve.

[0030] Compared with the prior art, the present invention has the following characteristics:

[0031] In this invention, after adding silver nickelate and sintering at 700–720°C for 3 minutes, the nickel in the silver nickelate can exist in different valence states, such as divalent nickel (Ni). 2+ ) and trivalent nickel (Ni 3+ At high temperatures, due to the change in the valence state of nickel ions during sintering, divalent nickel is deposited on silicon dioxide, resulting in a black appearance. During high-temperature sintering, the originally silvery layer reflects a large amount of heat, affecting the glass sintering effect. In contrast, the black silver layer absorbs a large amount of heat, improving the degree of sintering.

[0032] This invention improves the sintering effect of conductive silver paste on automotive glass by adding silver nickelate, selecting the appropriate glass, and combining different combinations of metallic silver powders, thereby reducing the sintering temperature of the conductive silver paste. The resulting black conductive silver paste not only meets the technical requirements of lower sintering temperatures for existing thickened automotive glass and compatibility with black glaze, but also satisfies requirements for conductivity, solderability, and tin surface color. Detailed Implementation

[0033] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0034] The following are more detailed implementation examples, which further illustrate the technical solution of the present invention and the technical effects that can be obtained.

[0035] In the following embodiments, unless otherwise specified, the raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.

[0036] Example 1

[0037] A black conductive silver paste, the preparation method of which includes the following steps:

[0038] (1) Prepare 100g of material according to the following components and mass:

[0039] 85g of metallic silver powder;

[0040]

[0041] The silver powder used was silver micro powder 1#, with an average particle size of 2.6 μm, a tap density of 4.1 g / mL, and a loose packing density of 2.2 g / mL; silver micro powder 2#, with an average particle size of 2.1 μm, a tap density of 3.2 g / mL, and a loose packing density of 1.4 g / mL; and silver micro powder 3#, with an average particle size of 1.9 μm, a tap density of 2.8 g / mL, and a loose packing density of 1.3 g / mL.

[0042] The silver nickelate No. 1 (Shanghai Yunbang New Materials Co., Ltd.) used has a nickel content of 0.1wt% and a density of 10.5 g·cm³. -3 ;

[0043] The glass powder used has an average particle size of 1.5-2.5 μm and a coefficient of thermal expansion of 85 × 10⁻⁶. -7 / K, sintering temperature is 540-670℃, its composition and weight percentage are: 28% silicon dioxide, 6% niobium pentoxide, 0.5% ferric oxide, 8% sodium oxide, 13% boron oxide, 9.5% zinc oxide, 3% bismuth oxide, 9% titanium oxide, 1.5% manganese trioxide, 3.5% zirconium oxide, 4% yttrium oxide, 3% aluminum oxide, 3.5% lithium oxide, 7.5% potassium oxide; the preparation method is: the above components are mixed and melted at 1100℃, then annealed at 25℃, and then ball-milled to obtain glass powder;

[0044] The ethyl cellulose used was sourced from Shanghai Herlist Chemical Co., Ltd.

[0045] The organic additives used are 0.4g ED120 (Shanghai Yuyu New Material Technology Co., Ltd.), 0.2g DBP (Guangzhou Qisheng Trading Co., Ltd.), and 0.1g BYK333 (Hunan Youxin Material Technology Co., Ltd.);

[0046] (2) Preparation of organic carrier: Weigh ethyl cellulose and diethylene glycol butyl ether, then heat them to 70°C and keep the temperature constant. After the polymer resin is completely dissolved, filter it through a 400-mesh screen to remove impurities, and the organic carrier is obtained.

[0047] (3) Preparation of conductive silver paste: First, add the weighed ED120, DBP and BYK333 to the organic carrier and stir evenly. Then, weigh silver micro powder 1#, silver nickelate and glass powder and mix them thoroughly in the mixer. Then, use a high-speed disperser to disperse at high speed to obtain a uniform black paste.

[0048] (4) Production of black silver paste: The above black paste is ground in a three-roll mill. The fineness of the black silver paste is controlled at 12μm and the viscosity is 28Pa·S by fine adjustment of the rollers, thus preparing black conductive silver paste.

[0049] Example 2

[0050] A black conductive silver paste, the preparation method of which includes the following steps:

[0051] (1) Prepare 100g of material according to the following components and mass:

[0052]

[0053] The silver powder used was silver micro powder 1#, with an average particle size of 2.6 μm, a tap density of 4.1 g / mL, and a loose packing density of 2.2 g / mL; silver micro powder 2#, with an average particle size of 2.1 μm, a tap density of 3.2 g / mL, and a loose packing density of 1.4 g / mL; and silver micro powder 3#, with an average particle size of 1.9 μm, a tap density of 2.8 g / mL, and a loose packing density of 1.3 g / mL.

[0054] The silver nickelate No. 2 (Shanghai Yunbang New Materials Co., Ltd.) used has a nickel content of 10wt% and a density of 10.1 g·cm³. -3 ;

[0055] The glass powder used has an average particle size of 1.5-2.5 μm and a coefficient of thermal expansion of 85 × 10⁻⁶. -7 / K, sintering temperature is 540-670℃, its composition and weight percentage are: 28% silicon dioxide, 6% niobium pentoxide, 0.5% ferric oxide, 8% sodium oxide, 13% boron oxide, 9.5% zinc oxide, 3% bismuth oxide, 9% titanium oxide, 1.5% manganese trioxide, 3.5% zirconium oxide, 4% yttrium oxide, 3% aluminum oxide, 3.5% lithium oxide, 7.5% potassium oxide; the preparation method is: the above components are mixed and melted at 1100℃, then annealed at 25℃, and then ball-milled to obtain glass powder;

[0056] The ethyl cellulose used was sourced from Shanghai Herlist Chemical Co., Ltd.

[0057] The organic additives used are 0.4g ED120 (Shanghai Yuyu New Material Technology Co., Ltd.), 0.2g DBP (Guangzhou Qisheng Trading Co., Ltd.), and 0.1g BYK333 (Hunan Youxin Material Technology Co., Ltd.);

[0058] (2) Preparation of organic carrier: Weigh ethyl cellulose and diethylene glycol butyl ether, then heat them to 70°C and keep the temperature constant. After the polymer resin is completely dissolved, filter it through a 400-mesh screen to remove impurities, and the organic carrier is obtained.

[0059] (3) Preparation of conductive silver paste: First, add the weighed ED120, DBP and BYK333 to the organic carrier and stir evenly. Then, weigh silver micro powder 2#, silver nickelate and glass powder and mix them thoroughly in the mixer. Then, use a high-speed disperser to disperse at high speed to obtain a uniform black paste.

[0060] (4) Production of black silver paste: The above black paste is ground in a three-roll mill. The fineness of the black silver paste is controlled at 9μm and the viscosity is 26Pa·S by fine adjustment of the rollers, thus preparing black conductive silver paste.

[0061] Example 3

[0062] A black conductive silver paste, the preparation method of which includes the following steps:

[0063] (1) Prepare 100g of material according to the following components and mass:

[0064]

[0065] The silver powder used was silver micro powder 1#, with an average particle size of 2.6 μm, a tap density of 4.1 g / mL, and a loose packing density of 2.2 g / mL; silver micro powder 2#, with an average particle size of 2.1 μm, a tap density of 3.2 g / mL, and a loose packing density of 1.4 g / mL; and silver micro powder 3#, with an average particle size of 1.9 μm, a tap density of 2.8 g / mL, and a loose packing density of 1.3 g / mL.

[0066] The silver nickelate No. 2 (Shanghai Yunbang New Materials Co., Ltd.) used has a nickel content of 15wt% and a density of 10.2 g·cm³. -3 ;

[0067] The glass powder used has an average particle size of 1.5-2.5 μm and a coefficient of thermal expansion of 85 × 10⁻⁶. -7 / K, sintering temperature is 540-670℃, its composition and weight percentage are: 28% silicon dioxide, 6% niobium pentoxide, 0.5% ferric oxide, 8% sodium oxide, 13% boron oxide, 9.5% zinc oxide, 3% bismuth oxide, 9% titanium oxide, 1.5% manganese trioxide, 3.5% zirconium oxide, 4% yttrium oxide, 3% aluminum oxide, 3.5% lithium oxide, 7.5% potassium oxide; the preparation method is: the above components are mixed and melted at 1100℃, then annealed at 25℃, and then ball-milled to obtain glass powder;

[0068] The ethyl cellulose used was sourced from Shanghai Herlist Chemical Co., Ltd.

[0069] The organic additives used are 0.4g ED120 (Shanghai Yuyu New Material Technology Co., Ltd.), 0.2g DBP (Guangzhou Qisheng Trading Co., Ltd.), and 0.1g BYK333 (Hunan Youxin Material Technology Co., Ltd.);

[0070] (2) Preparation of organic carrier: Weigh ethyl cellulose and diethylene glycol butyl ether, then heat them to 70°C and keep the temperature constant. After the polymer resin is completely dissolved, filter it through a 400-mesh screen to remove impurities, and the organic carrier is obtained.

[0071] (3) Preparation of conductive silver paste: First, add the weighed ED120, DBP and BYK333 to the organic carrier and stir evenly. Then, weigh silver micro powder 3#, silver nickelate and glass powder and mix them thoroughly in the mixer. Then, use a high-speed disperser to disperse at high speed to obtain a uniform black paste.

[0072] (4) Production of black silver paste: The above black paste is ground in a three-roll mill. The fineness of the black silver paste is controlled at 11 μm and the viscosity is 25 Pa·S by fine adjustment of the rollers, thus preparing black conductive silver paste.

[0073] Comparative Example 1

[0074] A conductive silver paste, the preparation method of which includes the following steps:

[0075] (1) Prepare 100g of material according to the following components and mass:

[0076]

[0077] The silver powder used was silver micro powder 1#, with an average particle size of 2.6 μm, a tap density of 4.1 g / mL, and a loose packing density of 2.2 g / mL; silver micro powder 2#, with an average particle size of 2.1 μm, a tap density of 3.2 g / mL, and a loose packing density of 1.4 g / mL; and silver micro powder 3#, with an average particle size of 1.9 μm, a tap density of 2.8 g / mL, and a loose packing density of 1.3 g / mL.

[0078] The glass powder used has an average particle size of 1.5-2.5 μm and a coefficient of thermal expansion of 85 × 10⁻⁶. -7 / K, sintering temperature is 540-670℃, its composition and weight percentage are: 28% silicon dioxide, 6% niobium pentoxide, 0.5% ferric oxide, 8% sodium oxide, 13% boron oxide, 9.5% zinc oxide, 3% bismuth oxide, 9% titanium oxide, 1.5% manganese trioxide, 3.5% zirconium oxide, 4% yttrium oxide, 3% aluminum oxide, 3.5% lithium oxide, 7.5% potassium oxide; the preparation method is: the above components are mixed and melted at 1100℃, then annealed at 25℃, and then ball-milled to obtain glass powder;

[0079] The ethyl cellulose used was sourced from Shanghai Herlist Chemical Co., Ltd.

[0080] The organic additives used are 0.4g ED120 (Shanghai Yuyu New Material Technology Co., Ltd.), 0.2g DBP (Guangzhou Qisheng Trading Co., Ltd.), and 0.1g BYK333 (Hunan Youxin Material Technology Co., Ltd.);

[0081] (2) Preparation of organic carrier: Weigh ethyl cellulose and diethylene glycol butyl ether, then heat them to 70°C and keep the temperature constant. After the polymer resin is completely dissolved, filter it through a 400-mesh screen to remove impurities, and the organic carrier is obtained.

[0082] (3) Preparation of conductive silver paste: First, add the weighed ED120, DBP and BYK333 to the organic carrier and stir evenly. Then, weigh silver micro powder 1# and glass powder and mix them thoroughly in the mixer. Then, use a high-speed disperser to disperse at high speed to obtain a uniform black paste.

[0083] (4) Production of black silver paste: The above black paste is ground in a three-roll mill. The fineness of the black silver paste is controlled to be 10 μm and the viscosity is 21 Pa·S by fine adjustment of the rollers, thus preparing black conductive silver paste.

[0084] Table 1. Performance test results of the conductive silver paste produced in Examples 1-3 and Comparative Example 1

[0085] Fineness / μm Viscosity / Pa·S Sintering at 630℃ for 5 minutes Glass tin surface color welding Example 1 12 28 Burn thoroughly black qualified Example 2 9 26 Burn thoroughly black qualified Example 3 11 25 Burn thoroughly black qualified Comparative Example 1 10 21 Not fully cooked Light reddish brown qualified

[0086] Remark:

[0087] Sintering process: First, black silver paste is screen-printed onto the frosted surface of the automotive glass. Then, it is dried in a drying oven at 150℃~180℃ for 5 minutes. After drying, the glass is placed in a high-temperature tunnel furnace with a temperature profile of 550℃~630℃ for tempering. The peak temperature of the tunnel furnace is 630℃, and the entire tempering time is 3~5 minutes. Finally, the color of the silver-tin surface is observed.

[0088] Welding: Before testing the welding tensile strength, the surface of the silver layer needs to be cleaned to remove oil, dust and other impurities to ensure welding quality. The solder is dripped onto the tongue beforehand, and then the tongue is fixed to the busbar. The tongue is heated until the solder melts on the silver layer. After cooling, the tongue is pulled vertically with a tensile testing machine until it separates from the silver layer. The force displayed by the tensile testing machine at this time is the maximum welding tensile strength of the silver layer (less than 80N is unqualified for welding, and greater than or equal to 80N is qualified).

[0089] In summary, compared with the comparative examples, adding silver nickelate can reduce the sintering temperature of silver paste. As the nickel content of silver nickelate in the examples increases, the color of the sintered silver paste becomes darker, but it has a certain impact on the welding of the silver layer. In Example 2, when the nickel content in the silver nickelate is 10%, the welding effect is good, and it can be completely burned through at 630°C for 5 minutes, with the best welding performance.

[0090] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A black conductive silver paste for automotive glass, characterized by, The silver powder is selected from at least one of silver powder 1#, silver powder 2# or silver powder 3#. The silver powder 1# has an average particle size of 2.6 μm, a tap density of 4.1 g / mL and a loose bulk density of 2.2 g / mL. The silver powder 2# has an average particle size of 2.1 μm, a tap density of 3.2 g / mL and a loose bulk density of 1.4 g / mL. The silver powder 3# has an average particle size of 1.9 μm, a tap density of 2.8 g / mL and a loose bulk density of 1.3 g / mL. The silver powder is a mixture of at least two of silver powder 1#, silver powder 2# or silver powder 3#. The silver powder is selected from at least one of silver powder 1#, silver powder 2# or silver powder 3#.

2. The black conductive silver paste for automotive glass according to claim 1, characterized by, The organic solvent is selected from at least one of terpineol, diethylene glycol butyl ether or dipropylene glycol monomethyl ether. The method comprises the following steps: S1: mixing and heating the polymer resin and the organic solvent to dissolve, filtering to obtain an organic carrier; S2: adding the organic additive to the organic carrier, mixing, and then adding the silver powder, silver nickelate and glass powder into a mixer to mix and disperse uniformly to obtain a uniform black paste; 3. The black conductive silver paste for automotive glass according to claim 1, characterized by, S3: grinding the black paste in a three-roll mill to control the fineness of the black silver paste to be less than 15 μm, and the viscosity to be 20-30 Pa·S to obtain a black conductive silver paste.

4. The black conductive silver paste for automotive glass according to claim 3, characterized by, In step S1, the temperature for heating and dissolving is 70-80 ℃, and in the filtering, a 300-400 mesh screen is used. The nickel content of the silver nickelate 1# is 0.1%, and the density is 10.5 g·cm -3 ; The nickel content of the silver nickelate 2# is 10%, and the density is 10.1 g·cm -3 ; The nickel content of the silver nickelate 3# is 15%, and the density is 10.2 g·cm -3 .

5. The black conductive silver paste for automotive glass according to claim 1, characterized by, The average particle size of the glass powder is 1.5-2.5μm, the coefficient of thermal expansion is 85x10 -7 / K, the sintering temperature is 540-670℃, and the glass powder comprises the following components and weight percentage: 28% silica, 6% niobium pentoxide, 0.5% ferric trioxide, 8% sodium oxide, 13% boron oxide, 9.5% zinc oxide, 3% bismuth oxide, 9% titanium oxide, 1.5% manganese trioxide, 3.5% zirconium oxide, 4% yttrium oxide, 3% aluminum oxide, 3.5% lithium oxide, 7.5% potassium oxide.

6. The black conductive silver paste for automotive glass according to claim 1, characterized by, ​ 7. A method of producing a black conductive silver paste for automotive glass according to any one of claims 1 to 6, characterized by, ​ ​ ​ ​ 8. The method for preparing black conductive silver paste for automotive glass according to claim 7, characterized in that, ​

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