Quick-dry conductive silver paste and preparation method thereof

Abstract

According to the quick-dry conductive silver paste and the preparation method thereof, the silver powder, the resin, the resin solvent, the dispersing agent, the antioxidant and the auxiliary solvent are used as raw materials, and the produced conductive silver paste can adapt to most of printers adopting a dispensing process and a silk-screen printing process in the market and is almost suitable for all substrates. The conductive silver paste disclosed by the invention can be quickly dried in a room-temperature environment, a generated conductive loop is excellent in performance, and the conductive silver paste can be suitable for preparing various fine conductive circuits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of conductive silver paste, and in particular, the present application relates to a preparation method capable of rapidly drying conductive silver paste and forming a conductive circuit. BACKGROUND

[0002] In the field of flexible electronic printing, conductive silver paste has been a widely used consumable, and its characteristics include but are not limited to high silver content, good conductivity of the formed conductive circuit, good stability, and different effects and application scenarios of various silver paste in different professional fields, such as repairing conductive circuits, SEM appearance performance detection, bonding components, etc.

[0003] In recent years, as the most basic consumable in the field of flexible electronic printing, conductive silver paste can quickly make conductive circuits through dispensing, screen printing and other methods, and the inventors have found that the post-processing methods of most conductive silver paste on the market are extremely complex, which is extremely inconvenient for users without heating or strong light curing conditions. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of quick-drying conductive silver paste, characterized in that it comprises the following steps:

[0005] (1) The conductive silver paste raw materials are configured according to the following proportions:

[0006]

[0007] (2) Mix the auxiliary solvent and the resin solvent, and stir under the condition of water bath heating until the solvent is no longer separated, and mix uniformly;

[0008] (3) Add the resin to the mixed solvent system. Stir until the system becomes transparent, and the resin no longer deposits at the bottom of the reaction container;

[0009] (4) Take the dispersant and antioxidant and add them to the reaction system, and stir until the reaction system is stable;

[0010] (5) After the reaction system presents a transparent gel liquid, add silver powder;

[0011] (6) Ultrasonic dispersion to obtain conductive silver paste.

[0012] Further, the silver powder in step (1) is selected from one or a mixture of several of flaky silver powder, spherical silver powder, rod-shaped silver powder, needle-shaped silver powder, dendritic silver powder, disc-shaped silver powder, and porous sponge-shaped silver powder;

[0013] The size of the silver powder ranges from 1 nm to 5 um (measured by the maximum size of the silver powder particles);

[0014] In the case of more than one kind of silver powder, in step (5), the reaction vessel is added with the silver powders in different shapes one after another, and each addition is spaced 5 minutes apart; until all kinds of silver powder are added in sufficient amount.

[0015] Further, in step (2),

[0016] The resin solvent is one or a mixture of several of liquid alcohol, ether, ester compound;

[0017] The auxiliary solvent is one or a mixture of several of liquid alcohol, ether, ketone, ester compound;

[0018] The heating condition is 50℃ water bath heating, and the stirring speed is 300rpm.

[0019] Further, in step (3), the resin is polymethyl methacrylate;

[0020] The stirring speed is 700rpm.

[0021] Further, in step (4), the dispersant is one or a mixture of several of polyisobutylene succinimide, polyvinyl alcohol, polyacrylic acid, lecithin;

[0022] The antioxidant is one or a mixture of several of benzotriazole, citric acid, polymethacrylic acid;

[0023] The stirring speed is 700rpm.

[0024] Further, in step (5), the silver powder used is flaky silver powder and spherical silver powder; the weight ratio of flaky silver powder to spherical silver powder is 1:10-10:1;

[0025] The stirring speed is 700rpm.

[0026] Further, in step (6), during ultrasonic dispersion, stirring is maintained for 2 hours under the ultrasonic dispersion condition; the stirring speed is 1100rpm.

[0027] Further, after the silver paste is stored for more than 30 days or obvious stratification and solidification phenomenon occurs, a diluent is added to ensure good flowability of the silver paste. The weight ratio of the diluent to the conductive silver paste is 1:5-5:1. The diluent is selected from one or a mixture of several of liquid ester, alcohol, ether, and all related auxiliary agents in step (1).

[0028] The present application also claims the quick-drying conductive silver paste obtained based on the above method.

[0029] The technical effect of the present application is self-evident. The conductive silver paste produced by the method has the characteristics of fast drying at room temperature to form a good power loop, short preparation period, fast curing speed, excellent conductive performance, and convenient production method, and has the beneficial effects of:

[0030] 1. The produced conductive silver paste can adapt to most dispensing processes and screen printing processes on the market;

[0031] 2. The ink is almost suitable for all substrates and can print good conductive lines on all substrates;

[0032] 3. The conductive silver paste in the present application can be quickly dried at room temperature. The specific experimental data shows that the surface drying and shaping are completed within 5 minutes, the stable electricity is completed within 30 minutes, and the complete drying is completed within 2H;

[0033] 4. The generated conductive loop has excellent performance, and the resistivity can be as low as 30uΩ·m;

[0034] 5. The conductive silver paste in the present application can be used for the preparation of various fine conductive lines, and the minimum line width is 45um. DETAILED DESCRIPTION

[0035] The present application will be further described below in conjunction with examples, but should not be understood as limiting the above-mentioned subject matter of the present application to the following examples. According to ordinary technical knowledge and conventional means in the art, various substitutions and modifications can be made without departing from the technical idea of the present application, and all should be included in the protection scope of the present application.

[0036] Example 1

[0037] A preparation method of a quick-drying conductive silver paste, characterized in that it comprises the following steps:

[0038] (1) The conductive silver paste raw materials are configured according to the following proportions:

[0039] Silver powder: 49%

[0040] Polymethyl methacrylate: 15%

[0041] Butyl acetate: 17.5%

[0042] Propylene glycol methyl ether acetate: 17.5%

[0043] PVPk30 dispersant: 0.5%

[0044] Benzotriazole: 0.5%

[0045] The silver powder is selected from spherical silver powder and flaky silver powder;

[0046] The proportion of silver powder is spherical silver powder: flaky silver powder = 3:1, and the size of silver powder ranges from 1 nm to 5 um.

[0047] (2) Butyl acetate and propylene glycol methyl ether acetate are mixed, and stirring is performed under the condition of water bath heating until the solvent is no longer separated, and the mixture is uniform; the heating condition is 50 DEG C water bath heating, and the stirring speed is 300 rpm.

[0048] (3) A sufficient amount of polymethyl methacrylate is added to the mixed solvent system. Stirring is performed until the system becomes transparent, and the resin is no longer deposited at the bottom of the reaction container; the stirring speed is 700 rpm.

[0049] (4) A sufficient amount of PVPK30 dispersant and benzotriazole is added to the reaction system, and stirring is performed until the reaction system is stable; the stirring speed is 700 rpm.

[0050] (5) After the reaction system presents a transparent gel liquid, silver powder is added and stirred; after the reaction system presents a transparent gel liquid, silver powder is added; spherical silver powder and flaky silver powder are added alternately, and each time the addition is spaced 5 min, until all types of sufficient silver powder are added. The stirring speed is 700 rpm.

[0051] (6) The conductive silver paste is prepared by ultrasonic dispersion. During ultrasonic dispersion, stirring is maintained for 2 h under the condition of ultrasonic dispersion; the stirring speed is 1100 rpm.

[0052] The prepared conductive silver paste is a viscous paste with silver gray color, and has a certain fluidity, and the overall viscosity is 370 mps·S. After coating and printing, the sheet resistance at 25 um film thickness is 4.738 Ω / □. The resistivity is 118.45 uΩ·m.

[0053] The printing of the conductive line by using the dispensing process is good, and the surface is dried within 15 min, the electricity is stabilized within 45 min, and the drying is completed within 2.5 h.

[0054] Example 2

[0055] A preparation method of a quick-drying conductive silver paste, characterized in that the method comprises the following steps:

[0056] (1) The raw materials of the conductive silver paste are configured according to the following proportions:

[0057] Silver powder: 69%

[0058] Polymethyl methacrylate: 5%

[0059] Butyl acetate: 10.5%

[0060] Propylene glycol methyl ether acetate: 10.5%

[0061] PVPk30 dispersant: 2.5%

[0062] benzotriazole: 2.5%;

[0063] The silver powder is selected from spherical silver powder, flaky silver powder, and rod-shaped silver powder.

[0064] The proportion of the silver powder is spherical silver powder: flaky silver powder: rod-shaped silver powder = 1:1:1, and the size of the silver powder ranges from 1 nm to 5 um.

[0065] (2) Butyl acetate and propylene glycol methyl ether acetate are mixed, and stirring is performed under the condition of water bath heating until the solvent is no longer separated, and the mixture is uniform; the heating condition is 50°C water bath heating, and the stirring speed is 300 rpm.

[0066] (3) A sufficient amount of polymethyl methacrylate is added to the mixed solvent system. Stirring is performed until the system becomes transparent, and the resin is no longer deposited at the bottom of the reaction container; the stirring speed is 700 rpm.

[0067] (4) A sufficient amount of PVPK30 dispersant and benzotriazole is added to the reaction system, and stirring is performed until the reaction system is stable; the stirring speed is 700 rpm.

[0068] (5) After the reaction system presents a transparent gel liquid, a sufficient amount of silver powder is sampled, and is added to the reaction container according to the shape of the silver powder. Each time, the interval is 5 min. Until all types of sufficient silver powder are added; the stirring speed is 700 rpm.

[0069] (6) The conductive silver paste is prepared by ultrasonic dispersion. During ultrasonic dispersion,

[0070] The prepared conductive silver paste is a viscous paste with a certain flowability, and has a whole viscosity of 450 mps·S. After printing, the sheet resistance at 25 um film thickness is 2.136 Ω / □, and the resistivity is 53.4 uΩ·m.

[0071] The printing of the conductive line by using the dispensing process is good, and the surface is dried within 5 min, the electricity is stabilized within 30 min, and the drying is completed within 2H.

[0072] Example 3

[0073] A preparation method of a quick-drying conductive silver paste, characterized in that the method comprises the following steps:

[0074] (1) The raw materials of the conductive silver paste are configured according to the following proportions:

[0075] Silver powder: 70.5%, polymethyl methacrylate: 5%, butyl acetate: 8%, propylene glycol methyl ether acetate: 12%, BYK-163 dispersant: 3%, benzotriazole: 0.5%;

[0076] The silver powder is selected from spherical silver powder, flaky silver powder;

[0077] The proportion of the silver powder is spherical silver powder: flaky silver powder = 1:1, and the size range of the silver powder is 1 nm-5 um;

[0078] (2) Butyl acetate and propylene glycol methyl ether acetate are mixed, and stirring is carried out under the condition of water bath heating until the solvent is no longer separated, and the mixture is uniform; the heating condition is 50°C water bath heating, and the stirring speed is 300 rpm.

[0079] (3) A sufficient amount of polymethyl methacrylate is added to the mixed solvent system. Stirring is carried out until the system becomes transparent, and the resin no longer deposits at the bottom of the reaction container; the stirring speed is 700 rpm.

[0080] (4) A sufficient amount of BYK-163 dispersant and benzotriazole is added to the reaction system, and stirring is carried out until the reaction system is stable; the stirring speed is 700 rpm.

[0081] (5) After the reaction system presents a transparent gel liquid, a sufficient amount of silver powder is sampled, and is added to the reaction container according to the shape of the silver powder. Each time, the interval is 5 min. Until all types of sufficient silver powder are added; the stirring speed is 700 rpm.

[0082] (6) The conductive silver paste is prepared by ultrasonic dispersion. During ultrasonic dispersion, stirring is maintained for 2 h under the condition of ultrasonic dispersion; the stirring speed is 1100 rpm.

[0083] The prepared conductive silver paste is a viscous paste with a certain flowability, and the overall viscosity is 540 mps·S. After printing, the sheet resistance at 25 um film thickness is 1.271 Ω / □, and the resistivity is 31.775 uΩ·m.

[0084] The printing of the conductive line by using the dispensing process is good, which is manifested by the surface drying within 5 min, the stable electricity within 30 min, and the complete drying within 2H.

Claims

1. A method for preparing a quick-drying conductive silver paste, characterized by, The method comprises the following steps: (1) configuring the conductive silver paste raw materials according to the following proportions: (2) mixing the auxiliary solvent and the resin solvent, stirring under the condition of water bath heating until the solvents are no longer separated, and mixing uniformly; (3) adding the resin into the mixed solvent system, stirring until the system becomes transparent, and the resin no longer deposits at the bottom of the reaction container; (4) taking the dispersant and the antioxidant and adding them into the reaction system, stirring until the reaction system is stable; (5) after the reaction system presents a transparent gel liquid, adding silver powder; (6) preparing the conductive silver paste through ultrasonic dispersion.

2. The method according to claim 1, characterized in that: the silver powder in step (1) is selected from one or a mixture of several of flaky silver powder, spherical silver powder, rod-shaped silver powder, needle-shaped silver powder, dendritic silver powder, disc-shaped silver powder, and porous sponge-shaped silver powder; the size of the silver powder ranges from 1 nm to 5 um; in the case of more than one kind of silver powder, in step (5), the reaction container is added with the silver powders in different shapes in sequence, and each addition is spaced 5-10 min; 3. The method of claim 1, wherein the method is characterized by: in step (2), the resin solvent is one or a mixture of several of liquid alcohol, ether, and ester compounds; the auxiliary solvent is one or a mixture of several of liquid alcohol, ether, ketone, and ester compounds; the heating condition is water bath heating at 35-50℃, and the stirring speed is 200-300 rpm.

4. The method of claim 1, wherein the method is characterized by: in step (3), the resin is polymethyl methacrylate; the stirring speed is 500-700 rpm.

5. The method of claim 1, wherein the method is characterized by: in step (4), the dispersant is one or a mixture of several of polyisobutylene succinimide, polyvinyl alcohol, polyacrylic acid, and lecithin; the antioxidant is one or a mixture of several of benzotriazole, citric acid, and polymethyl methacrylate; the stirring speed is 500-700 rpm.

6. The method of claim 1, wherein the method is characterized by: in step (5), the silver powder used is flaky silver powder and spherical silver powder, and the weight ratio of the flaky silver powder to the spherical silver powder is 1:10-10:1; the stirring speed is 500-700 rpm.

7. The method of claim 1, wherein the method is characterized by: in step (6), during ultrasonic dispersion, stirring is maintained for 1-2 h under the condition of ultrasonic dispersion, and the stirring speed is 900-1100 rpm.

8. A quick-drying conductive silver paste obtained based on the method according to any one of claims 1-7.

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