High-film-thickness conductive silver paste for GPS ceramic antennas, preparation method therefor and use thereof

Abstract

A high-film-thickness conductive silver paste for GPS ceramic antennas, a preparation method therefor and a use thereof. The conductive silver paste is prepared from the following components in percentage by weight: 75%-85% of conductive silver powder, 2%-4% of an organic binder, 3%-5% of an inorganic binder, 8%-18% of a solvent and 0.5%-1.5% of an auxiliary agent; the conductive silver powder is spherical silver powder, and the D50 particle size of the conductive silver powder is less than 1 μm; and the organic binder comprises one or more of ethyl cellulose, nitrocellulose, wood rosin, ethyl hydroxyethyl cellulose and acrylic resin; and the inorganic binder is lead-free glass powder with the D50 particle size of less than 1 μm. The conductive silver paste is large in viscosity and high in film thickness (greater than 7 μm), a welding head does not fall off, the welding strength is significantly enhanced, and the welding problem caused by silver consumption in small devices is improved, resulting in better adaptability.

Description

A high-thickness conductive silver paste for GPS ceramic antennas, and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of conductive materials, and in particular to a high-thickness conductive silver paste for GPS ceramic antennas, and a preparation method and application thereof. Background Art

[0002] In the existing technology, conductive and thermal conductive bonding in room temperature curing welding occasions, such as quartz crystals, infrared pyroelectric detectors, piezoelectric ceramics, potentiometers, flash tubes, shielding, circuit repair, etc. can also be used for conductive bonding in the radio instrumentation industry; it can also replace solder paste to achieve conductive bonding, and has a trend of gradually replacing traditional tin soldering. Therefore, the scope of application is becoming wider and wider, and the output is also gradually expanding.

[0003] As the most important receiving component in navigation and positioning equipment, the GPS antenna acts like a human ear, converting electromagnetic wave energy transmitted by satellites into an electric current that can be analyzed by electronic devices. Therefore, the performance of the conductive silver paste used in GPS ceramic antennas is directly related to the performance of the entire GPS device.

[0004] At present, the conductive silver paste for GPS ceramic antennas used in China mostly relies on foreign imports. The quality of domestically produced products is uneven, and the main problems are as follows: the viscosity of the conductive silver paste for GPS ceramic antennas is relatively low (40-50Pa·S), which cannot meet the demand for high film thickness. As a result, in the case of "silver consumption", the welding strength cannot meet the use requirements.

[0005] Summary of the Invention

[0006] The invention aims to provide a high-thickness conductive silver paste for GPS ceramic antennas, a preparation method and an application thereof, which has high viscosity and high film thickness.

[0007] The object of the present invention can be achieved by the following technical scheme: a high-thickness conductive silver paste for GPS ceramic antenna, the raw materials adopt the following components and weight percentage content: conductive silver powder 75% to 85%, organic binder 2% to 4%, inorganic binder 3% to 5%, solvent 8% to 18%, and additive 0.5% to 1.5%;

[0008] The conductive silver powder is spherical silver powder, and the D50 particle size of the conductive silver powder is less than 1 μm;

[0009] The organic binder includes one or more of ethyl cellulose, nitro cellulose, wood rosin, ethyl hydroxyethyl cellulose, and acrylic resin;

[0010] The inorganic binder is lead-free glass powder, and the D50 particle size of the lead-free glass powder is less than 1 μm.

[0011] Preferably, the conductive silver powder has a tap density of 1.5 to 4.0 g / ml and a bulk density of 0.5 to 2.0 g / ml.

[0012] Preferably, the organic binder is MF-400 nitrocellulose from Dow Chemical, ER-45M ethyl cellulose from Dow Chemical, B-814 acrylic resin from Covestro, or PAC-HV ethyl cellulose from Yanxing Chemical.

[0013] Preferably, the sintering temperature of the lead-free glass powder is 550-670°C.

[0014] Further preferably, the lead-free glass powder includes the following components and their weight percentages: Bi2O3 50%-70%, SiO2 7%-13%, B2O3 6%-30%, ZnO 4%-8%, TiO2 1%-10%, Al2O3 5%-14%, and ZrO 0%-1%.

[0015] Preferably, the solvent is one or a mixture of butyl ether, butyl carbitol acetate, diethylene glycol butyl ether, turpentine, terpineol, and terpineol.

[0016] Preferably, the auxiliary agent includes a plasticizer, a leveling agent, and a coupling agent.

[0017] Further preferably, the plasticizer includes one or more of dibutyl phthalate, tributyl citrate, dioctyl phthalate or trioctyl citrate.

[0018] Further preferably, the leveling agent includes one or more of an organic silicone leveling agent, hydrogenated castor oil, polyvinyl butyral or polyacrylate.

[0019] Further preferably, the coupling agent includes one or more of the silane coupling agents KH550, KH560 or KH570.

[0020] A method for preparing the high-thickness conductive silver paste for the GPS ceramic antenna comprises the following steps:

[0021] S1: Preparation of carrier: adding an organic binder to a portion of the solvent and heating and stirring to dissolve the organic binder until the organic binder is completely dissolved, filtering and removing impurities to obtain the carrier;

[0022] S2: Preparation of silver paste: Conductive silver powder, inorganic binder, additives, carrier, and remaining solvent are dispersed at a low speed, and then at a high speed to obtain a uniform slurry;

[0023] S3: The slurry obtained in step S2 is dispersed and ground in a three-roll mill to control the fineness to be below 15 μm and the viscosity to be between 100 Pa·s and 120 Pa·s, and then vacuum degassed to obtain the conductive silver paste.

[0024] Preferably, the heating, stirring and dissolving process in step S1 is carried out in a reactor at a heating temperature of 70 to 90°C.

[0025] Preferably, the filtering and impurity removal process in step S1 is performed using a 300-400 mesh filter.

[0026] Preferably, the low-speed dispersion rate in step S2 is 800-1200 r / min.

[0027] Preferably, the high-speed dispersion rate is 1800-2200 r / min.

[0028] Preferably, in step S3, the fineness is controlled to be below 15 μm by using a QXD0-100 scraper fineness meter.

[0029] Preferably, in step S3, the viscosity is controlled to be between 100 Pa·S and 120 Pa·S by using an NDJ-7 viscometer.

[0030] An application of the high-thickness conductive silver paste for GPS ceramic antennas is to coat the conductive silver paste on a PS ceramic antenna with a dry film thickness greater than 7 μm.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Compared with the existing technology, the high-thickness conductive silver paste for GPS ceramic antennas of the present invention has a higher viscosity, from 40-50 Pa·s to 100-120 Pa·s, which solves the problem of spreading during the screen printing process and has higher film thickness and resolution.

[0033] 2. The high-thickness conductive silver paste for GPS ceramic antennas of this invention overcomes the drawback of the existing insufficient dry film thickness (4-5 μm) by increasing the dry film thickness to >7 μm. This improves the problem of "silver erosion" during welding, significantly enhances welding strength, and has greater tensile strength. It also has better adaptability in small devices.

[0034] 3. The resin used in the high-thickness conductive silver paste for GPS ceramic antennas of the present invention is an imported resin with a suitable molecular weight and product stability. It has good solubility in organic solvents, and the prepared carrier has high viscosity and excellent screen printing performance.

[0035] 4. The particle sizes of the conductive silver powder and inorganic binder in the high-thickness conductive silver paste for GPS ceramic antennas of the present invention are both less than 1 μm, which provides better dispersion in the carrier, enhances the rheological properties of the paste, and improves the arrangement of silver paste lines. At the same time, the infiltration and sintering between the glass powder and the silver powder is more dense, and the silver film has higher adhesion after firing.

[0036] 5. The plasticizer, leveling agent, and coupling agent added to the high-thickness conductive silver paste for GPS ceramic antennas of the present invention make the conductive silver paste have better wetting, dispersion, and thixotropic properties. The lines in the silk screen printing process are full, the line edges are straight and burr-free, and there is no breakage or shrinkage.

[0037] 6. The conductive silver paste of the present invention has high viscosity and high film thickness (>7μm), the welding head does not fall off, the welding strength is significantly enhanced, and the welding problem caused by "silver consumption" in small devices is improved, and it has better adaptability;

[0038] 7. The conductive silver paste of the present invention still has excellent welding strength in the presence of "silver eating", thereby improving the application range of the conductive silver paste for GPS ceramic antennas. DETAILED DESCRIPTION

[0039] The embodiments of the present invention are described in detail below. The following embodiments are implemented based on the technical solutions of the present invention, and provide detailed implementation methods and specific operating processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0040] The raw materials used in the following examples and comparative examples are:

[0041] The spherical silver powder of Examples 1 to 3 is WX-4 from Hongxing, the ethyl cellulose is ER-45M from Dow, the nitrocellulose is MF-400 from Dow, the acrylic resin is B-814 from Covestro, the lead-free glass powder is GP-478 from Corning, and the solvents and additives are universal.

[0042] In comparative example 1, the spherical silver powder is nps-08 produced by Guoyin, the ethyl cellulose is PAC-HV produced by Yanxing Chemical, the lead-free glass powder is D270 produced by AnmiVina, and the solvent and additive are universal.

[0043] Example 1

[0044] In this embodiment, a high-thickness conductive silver paste for GPS ceramic antennas is prepared, and the raw materials include the following components and weight percentages: 75% conductive silver powder; 4% organic binder; 4% inorganic binder; 16.2% solvent; and 0.8% additives (plasticizer, leveling agent, and coupling agent).

[0045] The conductive silver powder is spherical silver powder with a D50 particle size of 0.83 μm, a tap density of 3.2 g / ml, and a loose density of 0.9 g / ml.

[0046] The organic binder is ethyl cellulose.

[0047] The inorganic binder is lead-free glass powder with a D50 particle size of 0.83 μm.

[0048] The solvent is a mixture of butyl ether, diethylene glycol butyl ether and terpineol.

[0049] The plasticizer is dibutyl phthalate.

[0050] The leveling agent is an organic silicon leveling agent.

[0051] The coupling agent is silane coupling agent KH570.

[0052] Preparation of S1 carrier: Weigh ethyl cellulose, diethylene glycol butyl ether and terpineol, then heat them to 80°C and maintain the temperature. After the ethyl cellulose is completely dissolved, filter on a 300-mesh mesh to remove impurities to obtain the carrier;

[0053] Preparation of S2 silver paste: Weigh the conductive silver powder, inorganic binder, plasticizer, leveling agent, coupling agent, carrier, and butyl ether in a mixer and disperse them thoroughly at a low speed, then use a high-speed disperser to disperse them at a high speed to obtain a uniform slurry;

[0054] Production of S3 silver paste: The above-mentioned paste is ground in a three-roll mill. The fineness of the silver paste is controlled to be below 10μm and the viscosity is controlled to 103Pa·s by fine adjustment of the rollers. This is to produce a high-thickness conductive silver paste for GPS ceramic antennas.

[0055] Example 2

[0056] In this embodiment, a high-thickness conductive silver paste for GPS ceramic antennas is prepared, and the raw materials use the following components and weight percentages: 80% conductive silver powder; 3% organic binder; 3% inorganic binder; 13% solvent; and 1% additives (plasticizer + leveling agent + coupling agent).

[0057] The conductive silver powder is spherical silver powder with a D50 particle size of 0.83 μm, a tap density of 3.2 g / ml, and a loose density of 0.9 g / ml.

[0058] The organic binder is ethyl cellulose and nitro cellulose, with a mass ratio of 1:1.

[0059] The inorganic binder is lead-free glass powder with a D50 particle size of 0.83 μm.

[0060] The solvent is a mixture of butyl ether and butyl carbitol acetate.

[0061] The plasticizer is dioctyl phthalate.

[0062] The leveling agent is hydrogenated castor oil.

[0063] The coupling agent is silane coupling agent KH550.

[0064] Preparation of S1 carrier: Weigh ethyl cellulose, nitrocellulose and butyl carbitol acetate, then heat them to 80°C and maintain the temperature. After the ethyl cellulose and nitrocellulose are completely dissolved, filter on a 300-mesh mesh to remove impurities, thereby obtaining the carrier;

[0065] Preparation of S2 silver paste: Weigh the conductive silver powder, inorganic binder, plasticizer, leveling agent, coupling agent, carrier, and butyl ether in a mixer at low speed for thorough mixing, and then use a high-speed disperser for high-speed dispersion to obtain a uniform slurry;

[0066] Production of S3 silver paste: The above-mentioned paste is ground in a three-roll mill. The fineness of the silver paste is controlled to be below 10μm and the viscosity is controlled to 110Pa·s by fine adjustment of the rollers. This is to produce a high-thickness conductive silver paste for GPS ceramic antennas.

[0067] Example 3

[0068] In this embodiment, a high-thickness conductive silver paste for GPS ceramic antennas is prepared, and the raw materials use the following components and weight percentages: 85% conductive silver powder; 2% organic binder; 3% inorganic binder; 9% solvent; and 1% additives (plasticizer + leveling agent + coupling agent).

[0069] The conductive silver powder is spherical silver powder with a D50 particle size of 0.83 μm, a tap density of 3.2 g / ml, and a loose density of 0.9 g / ml.

[0070] The organic binder is acrylic resin.

[0071] The inorganic binder is lead-free glass powder with a D50 particle size of 0.83 μm.

[0072] The solvent is a mixture of butyl carbitol acetate, diethylene glycol butyl ether and terpineol.

[0073] The plasticizer is tributyl citrate.

[0074] The leveling agent is polyacrylate.

[0075] The coupling agent is silane coupling agent KH550.

[0076] Preparation of S1 carrier: Weigh acrylic resin, butyl carbitol acetate, diethylene glycol butyl ether, and terpineol, then heat them to 80°C and maintain the temperature. After the acrylic resin is completely dissolved, filter on a 300-mesh mesh to remove impurities to obtain the carrier;

[0077] Preparation of S2 silver paste: Weigh the conductive silver powder, inorganic binder, plasticizer, leveling agent, coupling agent, carrier, and diethylene glycol butyl ether in a mixer and disperse them thoroughly at a low speed, then use a high-speed disperser to disperse them at a high speed to obtain a uniform slurry;

[0078] Production of S3 silver paste: The above-mentioned paste is ground in a three-roll mill. The fineness of the silver paste is controlled to below 10μm and the viscosity to 118Pa·s by fine adjustment of the rollers. This is to produce a high-thickness conductive silver paste for GPS ceramic antennas.

[0079] Comparative Example 1

[0080] In this comparative example, a conductive silver paste for GPS ceramic antenna is prepared, and the raw materials thereof are as follows in terms of weight percentage: 75% conductive silver powder; 4% organic binder; 4% inorganic binder; 16.2% solvent; and 0.8% additives (plasticizer, leveling agent, and coupling agent).

[0081] The conductive silver powder is spherical silver powder with a D50 particle size of 2 μm, a tap density of 2.4 g / ml, and a loose density of 0.7 g / ml.

[0082] The organic binder is domestic ethyl cellulose.

[0083] The inorganic binder is lead-free glass powder with a D50 particle size of 3 μm and a sintering temperature of 650°C. It includes the following components and their weight percentages: Bi2O3 65%, SiO2 17%, B2O3 8%, ZnO 6%, Na2O 0.5%, Al2O3 2%, and ZrO2 1.5%.

[0084] The solvent is a mixture of butyl ether, diethylene glycol butyl ether and terpineol.

[0085] The plasticizer is dibutyl phthalate.

[0086] The leveling agent is an organic silicon leveling agent.

[0087] The coupling agent is silane coupling agent KH570.

[0088] Preparation of S1 carrier: Weigh ethyl cellulose, diethylene glycol butyl ether and terpineol, then heat them to 80°C and maintain the temperature. After the ethyl cellulose is completely dissolved, filter on a 300-mesh mesh to remove impurities to obtain the carrier;

[0089] Preparation of S2 silver paste: Weigh the conductive silver powder, inorganic binder, plasticizer, leveling agent, coupling agent, carrier, and butyl ether in a mixer at low speed for thorough mixing, and then use a high-speed disperser for high-speed dispersion to obtain a uniform slurry;

[0090] Production of S3 silver paste: The above-mentioned paste is ground in a three-roll mill. The fineness of the silver paste is controlled to be below 10μm and the viscosity is controlled to 47Pa·s by fine adjustment of the rollers. This is the conductive silver paste for GPS ceramic antennas.

[0091] The performance of the silver paste for GPS ceramic antenna prepared in Examples 1 to 3 and Comparative Example 1 was tested. The test results are listed in Table 1:

[0092] Table 1: Performance test results of conductive silver paste for GPS ceramic antenna

[0093] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. 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 present invention, should be within the scope of protection of the present invention.

Claims

1. A high-thickness conductive silver paste for GPS ceramic antenna, characterized in that: The raw materials use the following components and weight percentages: conductive silver powder 75% to 85%, organic binder 2% to 4%, inorganic binder 3% to 5%, solvent 8% to 18%, and additive 0.5% to 1.5%; The conductive silver powder is spherical silver powder, and the D50 particle size of the conductive silver powder is less than 1 μm; The organic binder includes one or more of ethyl cellulose, nitro cellulose, wood rosin, ethyl hydroxyethyl cellulose, and acrylic resin; The inorganic binder is lead-free glass powder, and the D50 particle size of the lead-free glass powder is less than 1 μm.

2. The high-thickness conductive silver paste for GPS ceramic antenna according to claim 1, characterized in that: The tap density of the conductive silver powder is 1.5-4.0 g / ml, and the loose density is 0.5-2.0 g / ml.

3. The high-thickness conductive silver paste for GPS ceramic antenna according to claim 1, characterized in that: The sintering temperature of the lead-free glass powder is 550-670°C.

4. The high-thickness conductive silver paste for GPS ceramic antenna according to claim 3, characterized in that: The lead-free glass powder includes the following components and their weight percentages: Bi2O3 50%-70%, SiO2 7%-13%, B2O3 6%-30%, ZnO 4%-8%, TiO2 1%-10%, Al2O3 5%-14%, and ZrO 0%-1%.

5. The high-thickness conductive silver paste for GPS ceramic antenna according to claim 1, characterized in that: The solvent is one or a mixture of butyl ether, butyl carbitol acetate, diethylene glycol butyl ether, turpentine, terpineol and terpineol.

6. The high-thickness conductive silver paste for GPS ceramic antenna according to claim 1, characterized in that: The auxiliary agents include plasticizers, leveling agents and coupling agents.

7. The high-thickness conductive silver paste for GPS ceramic antenna according to claim 6, characterized in that: The plasticizer includes one or more of dibutyl phthalate, tributyl citrate, dioctyl phthalate or trioctyl citrate; The leveling agent includes one or more of an organic silicon leveling agent, hydrogenated castor oil, polyvinyl butyral or polyacrylate; The coupling agent includes one or more of silane coupling agents KH550, KH560 or KH570.

8. A method for preparing a high-thickness conductive silver paste for GPS ceramic antenna according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Preparation of carrier: adding organic binder to part of solvent, heating and stirring to dissolve, filtering and removing impurities to obtain carrier; S2: Preparation of silver paste: Disperse the conductive silver powder, inorganic binder, additive, carrier and remaining solvent at a low speed, and then disperse at a high speed to obtain a uniform slurry; S3: The slurry obtained in step S2 is dispersed and ground in a three-roll mill to control the fineness to be below 15 μm and the viscosity to be between 100 Pa·S and 120 Pa·S, and then vacuum degassed to obtain the conductive silver paste.

9. The method for preparing a high-thickness conductive silver paste for GPS ceramic antenna according to claim 8, characterized in that: The low-speed dispersion rate is 800-1200 r / min; The high-speed dispersion rate is 1800-2200 r / min.

10. An application of the high-thickness conductive silver paste for GPS ceramic antenna according to any one of claims 1 to 7, characterized in that: The conductive silver paste is coated on the PS ceramic antenna, and the dry film thickness is greater than 7 μm.

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