Special thick film material for electronic component as well as preparation and application of special thick film material

Abstract

The invention relates to the technical field of thick-film electronic materials, in particular to a thick-film material special for an electronic element and preparation and application of the thick-film material. The special thick film material for the electronic component is obtained by uniformly mixing a glass adhesive, a composite conductive material, an organic carrier and a surfactant, wherein the composite conductive material is prepared by coating a carbon nanotube with starch sodium octenylsuccinate and loading a silver nanowire; polyoxyethylene nonyl phenyl ether and hexadecyl trimethyl ammonium chloride are used for regulating and controlling growth of silver nanowires on the surface of a carbon nanotube coated with starch sodium octenylsuccinate, the conductive silver nanowires which are regularly arranged and good in dispersity are obtained, and the conductive silver nanowires are applied to a special thick film material for electronic elements. The use amount of the conductive silver paste in the thick film material special for the electronic component is obviously reduced, and the conductivity is improved.

Description

Technical Field

[0001] The invention relates to the technical field of thick film electronic materials, in particular to a special thick film material for electronic components and the preparation and application thereof. Background Art

[0002] With the development of science and technology, electronic technology is developing towards high frequency, miniaturization and high integration. Integrated circuits, as an important crystallization of the development of contemporary electronic technology, are composed of three major parts: semiconductor integrated circuits, thin-film hybrid integrated circuits and thick-film hybrid integrated circuits. Thick-film circuits are the abbreviation of thick-film hybrid integrated circuits that have irreplaceable roles in high temperature and high voltage.

[0003] Thick film circuit is a circuit unit with specific functions such as resistors and inductors made by screen printing and sintering electronic paste on substrate. Compared with thin film hybrid circuit, thick film circuit has more flexible design, simple process and low cost. Therefore, the dominant position of thick film circuit in the hybrid circuit industry is becoming more and more obvious. The material basis of thick film circuit is substrate and electronic paste. Substrate is the carrier, and electronic paste is the core of thick film circuit. After nearly 20 years of development, the stability and precision of electronic paste have been greatly improved. With the development of science and technology, new electronic pastes are constantly being discovered, their functions are becoming more and more perfect, and their application fields have also been expanded.

[0004] The development and application of thick film resistor paste benefited from the emergence of screen printing technology in the 1950s. In the late 1960s, DuPont of the United States took the lead in successfully developing a series of ruthenium dioxide resistor pastes with a wide resistance range, excellent resistance stability and repeatability. After the 1970s, the conductive mechanism and model of thick film resistors were also proposed one after another. In the 1980s, based on the previous scientific research, scientists conducted systematic research on the preparation process of thick film resistors, improved the performance of resistor pastes, and promoted the development of resistor pastes.

[0005] Since the 1990s, the performance of thick film resistor pastes has been greatly improved. High-performance thick film resistor pastes developed by companies represented by DuPont in the United States, such as Birox2000 series thick film resistor pastes, are widely used in industrial production. The RU series thick film resistor paste developed by SMM in Japan can produce thick film resistors with a square resistance range of 0.1Ω / □-10MΩ / □ after sintering.

[0006] With the development of new technologies, low cost, lead-free, and high cost performance have become new development directions for electronic pastes. Some base metal materials have the characteristics of conductive phase materials, which has led to the rapid development of resistor pastes. By compounding electronic pastes to obtain cost-effective electronic pastes, thick film resistors used in special environments can be prepared.

[0007] CN 113643869 A discloses a resistor paste for high-stability thick film resistors, which is composed of 15%-40% conductive powder, 25%-45% modified glass powder, 1%-5% inorganic additives, and 25%-35% organic carriers by mass percentage. The precious metal powder in the conductive powder is one or more of silver, palladium, silver-palladium alloy powder, and ruthenium dioxide. The conductive material used is a precious metal, and the amount is extremely large, resulting in serious loss. Therefore, it is very necessary to develop a new conductive material for thick film resistors. Summary of the invention

[0008] In view of the defects of the prior art, the present invention provides a thick film material specially used for electronic components, which is composed of the following raw materials: a conductive phase material, a glass phase material, an organic carrier, and a modifier.

[0009] A method for preparing a thick film material for electronic components comprises the following steps:

[0010] (1) Preparation of organic carrier: Heat and stir the organic solvent and thickener until the thickener is completely dissolved, then add castor oil and stir evenly at constant temperature, cool to room temperature and store for future use;

[0011] (2) Preparation of glass binder: Calcium oxide, boron trioxide, silicon dioxide and water are mixed and ball-milled for 10-14 hours, taken out and dried, and then calcined at 1300-1500° C. for 1.5-3 hours to obtain molten glass liquid, which is poured into water, cooled and dried to obtain glass slag, which is preliminarily ground and sieved through a 180-250 mesh sieve to obtain coarse glass powder, and then anhydrous ethanol and coarse glass powder are mixed, ball-milled and sieved through a 300-400 mesh sieve to obtain a glass binder;

[0012] (3) Evenly mixing the glass binder, the composite conductive material, the organic carrier, and the surfactant to obtain the special thick film material for electronic components.

[0013] Preferably, the method for preparing the thick film material for electronic components comprises the following steps:

[0014] (1) Preparation of an organic carrier: 80-85 parts of an organic solvent and 4-6 parts of a thickener are mixed uniformly by weight, heated to 85-95° C., stirred at 160-200 r / min for 10-20 min, then 3-5 parts of castor oil are added, and the mixture is stirred at 85-95° C. and 160-200 r / min for 1-3 h, and then cooled to room temperature to obtain an organic carrier;

[0015] (2) Preparation of glass binder: by weight, 2-3 parts of calcium oxide, 1-2 parts of boron trioxide, 2-3 parts of silicon dioxide, and 5-7 parts of water are mixed and ball-milled for 10-14 hours, taken out and dried, and then calcined at 1300-1500°C for 1-3 hours to obtain molten glass liquid; the molten glass liquid is poured into water, cooled, taken out and dried to obtain glass slag; the glass slag is ground and passed through a 180-250 mesh sieve to obtain glass coarse powder; then 1-2 parts of anhydrous ethanol and 1-2 parts of glass coarse powder are mixed evenly, ball-milled for 2-4 hours, and passed through a 300-400 mesh sieve to obtain a glass binder;

[0016] (3) By weight, 0.1-0.5 parts of glass binder, 0.1-0.5 parts of composite conductive material, 0.1-0.5 parts of organic carrier, and 0.005-0.015 parts of surfactant are mixed, and stirred at a speed of 200-300 r / min for 15-30 min to obtain the thick film material for electronic components.

[0017] The organic solvent is one or a mixture of two or more of terpineol, diethylene glycol butyl ether acetate, and tributyl citrate; preferably, the organic solvent is a mixture of terpineol, diethylene glycol butyl ether acetate, and tributyl citrate in a mass ratio of (55-65): (15-25): (1-10).

[0018] The thickener is one or a mixture of two or more of ethyl cellulose, hydroxyethyl cellulose and polyvinyl alcohol; preferably, the thickener is hydroxyethyl cellulose.

[0019] The surfactant is one of Tween 85 and Span; preferably, the surfactant is Tween 85.

[0020] The ball mill adopts one of a zirconium oxide ball mill and a nylon ball mill; preferably, the ball mill adopts a zirconium oxide ball mill. The ball mill medium is zirconium oxide balls, and the ball-to-material ratio is (1-2):1.

[0021] The method for preparing the composite conductive material comprises the following steps:

[0022] S1: adding 9-11 parts of carbon nanotubes to 180-210 parts of 40-60wt% concentrated nitric acid by weight, ultrasonically treating for 5-15 minutes, then heating to 110-130°C, stirring at 150-200r / min for 3-5 hours, cooling, centrifuging, washing and drying to obtain acidified carbon nanotubes;

[0023] S2: Dispersing 1-3 parts of acidified carbon nanotubes in 180-220 parts of water by mass, ultrasonically treating for 0.5-1h, then adding 1-2 parts of sodium starch octenyl succinate, and then reacting at 35-45°C and a stirring speed of 400-500r / min for 10-14h. After the reaction, filtering with a microporous filter membrane with a pore size of 0.4-0.5μm, washing and drying to obtain carbon nanotubes coated with sodium starch octenyl succinate;

[0024] S3: In parts by mass, 0.2-0.3 parts of sodium chloride, 5-6 parts of modifier, and 0.5-1 parts of carbon nanotubes coated with sodium starch octenyl succinate are added to 15-25 parts of ethylene glycol, and stirred at 200-300 r / min for 10-20 min, and then 1.5-2 parts of silver nitrate are added, and stirring is continued at 200-300 r / min for 20-40 min, and then heated to 160-180°C at a rate of 8-12°C / min in a nitrogen atmosphere, and stirring and nitrogen introduction are stopped. The reaction is continued for 1-2 hours, and the mixture is cooled to room temperature in an ice bath, and a composite conductive material is obtained by centrifugation, washing, and drying.

[0025] The ultrasonic frequency in steps S1 and S2 is 40-60kHz, and the power is 100-200W.

[0026] The modifier is one of nonylphenol polyoxyethylene ether and hexadecyl trimethyl ammonium chloride or a mixture of the two; preferably, the modifier is a mixture of nonylphenol polyoxyethylene ether and hexadecyl trimethyl ammonium chloride in a mass ratio of 5:(1-3).

[0027] The application of the above-mentioned thick film materials for electronic components in thick film electronic materials.

[0028] The specific application method is as follows: the above-mentioned electronic component-specific thick film material is printed on an alumina ceramic substrate by a screen printer, dried, then cured, and cooled to obtain a thick film resistor.

[0029] In order to reduce the amount of conductive silver paste used in a special thick film material for electronic components and improve its conductive performance, the present invention prepares a new composite conductive material and applies it to the special thick film material for electronic components.

[0030] First, the present invention uses a strong oxidizing acid to open the carbon-carbon bond at the port or defect of the carbon nanotube, and introduces active groups such as hydroxyl and carboxyl. Since nitric acid releases free oxygen atoms during the heating process, it combines with the carbon atoms on the carbon nanotube to form a -C=O group. At the same time, these free oxygen atoms combine with hydrogen ions and hydroxide ions in water, and have strong oxidizing properties. After oxidation, carboxyl groups can be formed on the surface of the carbon nanotube. Then, the carboxyl groups are used as active sites to adsorb silver ions and realize the growth of silver nanowires on the surface of the carbon nanotube. Here, the carbon nanotube is used as a substrate to regulate the growth of the silver nanowire so that the silver nanowire grows longitudinally along the carbon nanotube, thereby improving the orderliness of the silver nanowire. After high-temperature curing, the carbon nanotube disappears, and the silver nanowire is orderly arranged along the direction of the carbon nanotube and connected to each other to form a conductive chain. The chains are cross-linked to form a conductive network. Compared with directly adding silver nanowires, its dispersibility is better, the silver nanowire is longer, and the conductive network is more regular, thereby reducing the square resistance of the prepared electronic component special thick film material and improving its conductivity. However, its defects are very obvious. There are fewer carboxyl groups on the surface of carbon nanotubes and the silver loading is low, which will cause a large number of pores during the curing process, affecting the mechanical properties of the film and causing its resistance to be slightly higher.

[0031] Therefore, the present invention further coats the carbon nanotubes with sodium starch octenyl succinate. Since the surface of sodium starch octenyl succinate contains a large number of carboxyl groups, it has a strong chelating effect on silver ions and can adsorb a large number of silver ions, greatly increasing the loading amount of nanosilver, thereby increasing the silver content in the prepared composite conductive material.

[0032] Furthermore, since there are many silver ion adsorption sites on the surface of sodium starch octenyl succinate, the growth of silver nanowires is hindered. The present invention further uses nonylphenol polyoxyethylene ether and cetyltrimethylammonium chloride to regulate the growth direction of silver nanowires. Nonylphenol polyoxyethylene ether has a strong coating effect on silver nanowires, and controls the singleness of the growth direction of silver nanowires through coating, while cetyldimethylammonium chloride also has the effect of chelating nanosilver, which can reduce the amount of silver ions on the surface of sodium starch octenyl succinate and control the rate of silver ion reduction. The two act synergistically to obtain relatively regularly loaded silver nanowires on the surface of carbon nanotubes coated with sodium starch octenyl succinate, thereby improving their conductivity.

[0033] Beneficial effects of the present invention:

[0034] The special thick film material for electronic components of the present invention is obtained by uniformly mixing a glass adhesive, a composite conductive material, an organic carrier and a surfactant, wherein the composite conductive material adopts sodium starch octenyl succinate to coat carbon nanotubes and load silver nanowires, and nonylphenol polyoxyethylene ether and hexadecyltrimethylammonium chloride are used to regulate the growth of silver nanowires on the surface of the carbon nanotubes coated with sodium starch octenyl succinate, so as to obtain conductive silver nanowires with regular arrangement and good dispersibility, and the conductive silver nanowires are applied to the special thick film material for electronic components, so as to significantly reduce the amount of conductive silver paste in the special thick film material for electronic components and improve its conductive performance. DETAILED DESCRIPTION

[0035] Castor oil, item number: ZRHH-010, Shandong Zhongrun Haihua Chemical Technology Co., Ltd.

[0036] Zirconia balls: large balls: 2 mm in diameter; medium balls: 0.5 mm in diameter; small balls: 0.1 mm in diameter. The large balls, medium balls and small balls are mixed in a mass ratio of 1:2:1 to obtain the zirconia balls.

[0037] Terpineol, product number: T36060, Shanghai Jizhi Biochemical Technology Co., Ltd.

[0038] Hydroxyethyl cellulose, product number: S14167, Shanghai Yuanye Biotechnology Co., Ltd.

[0039] Tween 85, product number: S15021, Shanghai Yuanye Biotechnology Co., Ltd.

[0040] Carbon nanotubes, product number: A15675, Beijing Wokai Biotechnology Co., Ltd.

[0041] Sodium starch octenylsuccinate, product number: 6123020, Shenzhen Bell Pharmaceutical Technology Co., Ltd.

[0042] Nonylphenol polyoxyethylene ether, CAS number: 14409-72-4, item number: B65867, Shanghai Yuanye Biotechnology Co., Ltd.

[0043] Example 1

[0044] A method for preparing a thick film material for electronic components comprises the following steps:

[0045] (1) Preparation of an organic carrier: 84 parts of an organic solvent and 5 parts of a thickener were mixed uniformly by weight, heated to 90° C., and stirred at 180 r / min for 15 min, then 4 parts of castor oil were added, and the mixture was stirred at 90° C. and 180 r / min for 2 h, and then cooled to room temperature to obtain an organic carrier;

[0046] (2) Preparation of glass binder: 2.2 parts of calcium oxide, 1.4 parts of boron trioxide, 2.4 parts of silicon dioxide, and 6 parts of water were mixed by weight, ball-milled for 12 hours, taken out and dried, and then calcined at 1400°C for 2 hours to obtain molten glass liquid; the molten glass liquid was poured into water at a bath ratio of 1g:20mL, cooled, taken out and dried to obtain glass slag; the glass slag was ground and passed through a 200-mesh sieve to obtain glass coarse powder; then 1 part of anhydrous ethanol and 1 part of the glass coarse powder were mixed evenly, ball-milled for 3 hours, and passed through a 350-mesh sieve to obtain a glass binder;

[0047] (3) By weight, 0.4 parts of glass binder, 0.3 parts of composite conductive material, 0.3 parts of organic vehicle, and 0.01 parts of Tween 85 were mixed, and stirred at a speed of 230 r / min for 20 min to obtain the thick film material for electronic components.

[0048] The organic solvent is prepared by mixing pinene alcohol, diethylene glycol butyl ether acetate and tributyl citrate in a mass ratio of 60:19:5.

[0049] The thickener is hydroxyethyl cellulose.

[0050] The ball mill adopts a zirconia ball milling jar, the ball milling medium is zirconia balls, and the ball-to-material ratio is 1:1.

[0051] The preparation method of the composite conductive material comprises the following steps: adding 0.29 parts of sodium chloride and 5.5 parts of a modifier to 20 parts of ethylene glycol by mass, stirring at a speed of 280 r / min for 15 minutes, then adding 1.7 parts of silver nitrate, continuing to stir at a speed of 280 r / min for 30 minutes, heating to 170°C at a rate of 10°C / min in a nitrogen atmosphere, stopping stirring, stopping the introduction of nitrogen, continuing the reaction for 1 hour, cooling to room temperature in an ice bath, centrifuging, washing, and drying to obtain the composite conductive material.

[0052] The modifier is prepared by mixing nonylphenol polyoxyethylene ether and hexadecyl trimethyl ammonium chloride in a mass ratio of 5:3.

[0053] Example 2

[0054] A method for preparing a thick film material for electronic components comprises the following steps:

[0055] (1) Preparation of an organic vehicle: 84 parts of an organic solvent and 5 parts of a thickener were mixed, heated to 90° C., and stirred at 180 r / min for 15 min. Then, 4 parts of castor oil were added, and the mixture was stirred at 90° C. and 180 r / min for 2 h. Then, the mixture was cooled to room temperature to obtain an organic vehicle.

[0056] (2) Preparation of glass binder: 2.2 parts of calcium oxide, 1.4 parts of boron trioxide, 2.4 parts of silicon dioxide, and 6 parts of water were mixed by weight, ball-milled for 12 hours, taken out and dried, and then calcined at 1400°C for 2 hours to obtain molten glass liquid; the molten glass liquid was poured into water at a bath ratio of 1g:20mL, cooled, taken out and dried to obtain glass slag; the glass slag was ground and passed through a 200-mesh sieve to obtain glass coarse powder; then 1 part of anhydrous ethanol and 1 part of the glass coarse powder were mixed evenly, ball-milled for 3 hours, and passed through a 350-mesh sieve to obtain a glass binder;

[0057] (3) By weight, 0.4 parts of glass binder, 0.3 parts of composite conductive material, 0.3 parts of organic vehicle, and 0.01 parts of Tween 85 were mixed, and stirred at a speed of 230 r / min for 20 min to obtain the thick film material for electronic components.

[0058] The organic solvent is prepared by mixing pinene alcohol, diethylene glycol butyl ether acetate and tributyl citrate in a mass ratio of 60:19:5.

[0059] The thickener is hydroxyethyl cellulose.

[0060] The ball mill adopts a zirconia ball milling jar, the ball milling medium is zirconia balls, and the ball-to-material ratio is 1:1.

[0061] The method for preparing the composite conductive material comprises the following steps:

[0062] S1: adding 10 parts of carbon nanotubes to 200 parts of 46wt% concentrated nitric acid by weight, ultrasonically treating for 10 minutes, then heating to 120°C, stirring at 180r / min for 4 hours, cooling, centrifuging, washing and drying to obtain acidified carbon nanotubes;

[0063] S2: By mass, 0.29 parts of sodium chloride, 5.5 parts of modifier and 0.8 parts of acidified carbon nanotubes were added to 20 parts of ethylene glycol, stirred at 280 r / min for 15 min, and then 1.7 parts of silver nitrate were added. After stirring at 280 r / min for 30 min, the mixture was heated to 170°C at a rate of 10°C / min in a nitrogen atmosphere. Stirring and nitrogen introduction were stopped, and the reaction was continued for 1 h. The mixture was cooled to room temperature in an ice bath, and a composite conductive material was obtained by centrifugation, washing and drying.

[0064] The modifier is prepared by mixing nonylphenol polyoxyethylene ether and hexadecyl trimethyl ammonium chloride in a mass ratio of 5:3.

[0065] Example 3

[0066] A method for preparing a thick film material for electronic components comprises the following steps:

[0067] (1) Preparation of an organic carrier: 84 parts of an organic solvent and 5 parts of a thickener were mixed uniformly by weight, heated to 90° C., and stirred at 180 r / min for 15 min, then 4 parts of castor oil were added, and the mixture was stirred at 90° C. and 180 r / min for 2 h, and then cooled to room temperature to obtain an organic carrier;

[0068] (2) Preparation of glass binder: 2.2 parts of calcium oxide, 1.4 parts of boron trioxide, 2.4 parts of silicon dioxide and 6 parts of water were mixed by weight and ball-milled for 12 hours, taken out and dried, and then calcined at 1400°C for 2 hours to obtain molten glass liquid; the molten glass liquid was poured into water at a bath ratio of 1g:20mL, cooled and dried to obtain glass slag; the glass slag was ground and passed through a 200-mesh sieve to obtain glass coarse powder; then 1 part of anhydrous ethanol and 1 part of the glass coarse powder were mixed evenly and ball-milled for 3 hours, and passed through a 350-mesh sieve after ball milling to obtain glass binder;

[0069] (3) By weight, 0.4 parts of glass binder, 0.3 parts of composite conductive material, 0.3 parts of organic vehicle, and 0.01 parts of Tween 85 were mixed, and stirred at a speed of 230 r / min for 20 min to obtain the thick film material for electronic components.

[0070] The organic solvent is prepared by mixing pinene alcohol, diethylene glycol butyl ether acetate and tributyl citrate in a mass ratio of 60:19:5.

[0071] The thickener is hydroxyethyl cellulose.

[0072] The ball mill adopts a zirconia ball milling jar, the ball milling medium is zirconia balls, and the ball-to-material ratio is 1:1.

[0073] The method for preparing the composite conductive material comprises the following steps:

[0074] S1: adding 10 parts of carbon nanotubes to 200 parts of 46wt% concentrated nitric acid by weight and ultrasonically treating for 10 minutes, then heating to 120°C and stirring at 180r / min for 4 hours, cooling, centrifuging, washing and drying to obtain acidified carbon nanotubes;

[0075] S2: Disperse 2 parts of acidified carbon nanotubes in 200 parts of water and ultrasonically treat for 0.5 h, then add 1 part of sodium starch octenyl succinate, and then react for 12 h at 40°C and a stirring speed of 450 r / min. After the reaction, filter with a microporous filter membrane with a pore size of 0.45 μm, wash and dry to obtain carbon nanotubes coated with sodium starch octenyl succinate;

[0076] S3: In parts by mass, 0.29 parts of sodium chloride, 5.5 parts of modifier, and 0.8 parts of carbon nanotubes coated with sodium starch octenyl succinate were added to 20 parts of ethylene glycol, and stirred at 280 r / min for 15 min. Then, 1.7 parts of silver nitrate were added, and stirring was continued at 280 r / min for 30 min. Then, the mixture was heated to 170°C at a rate of 10°C / min in a nitrogen atmosphere. Stirring and nitrogen introduction were stopped, and the reaction was continued for 1 hour. The mixture was cooled to room temperature in an ice bath, and a composite conductive material was obtained by centrifugation, washing, and drying.

[0077] The ultrasonic frequency in steps S1 and S2 is 50kHz and the power is 160W.

[0078] The modifier is prepared by mixing nonylphenol polyoxyethylene ether and hexadecyl trimethyl ammonium chloride in a mass ratio of 5:3.

[0079] Example 4

[0080] A method for preparing a thick film material for electronic components comprises the following steps:

[0081] (1) Preparation of an organic carrier: 84 parts of an organic solvent and 5 parts of a thickener were mixed uniformly by weight, heated to 90° C., and stirred at 180 r / min for 15 min, then 4 parts of castor oil were added, and the mixture was stirred at 90° C. and 180 r / min for 2 h, and then cooled to room temperature to obtain an organic carrier;

[0082] (2) Preparation of glass binder: 2.2 parts of calcium oxide, 1.4 parts of boron trioxide, 2.4 parts of silicon dioxide, and 6 parts of water were mixed by weight, ball-milled for 12 hours, taken out and dried, and then calcined at 1400°C for 2 hours to obtain molten glass liquid; the molten glass liquid was poured into water at a bath ratio of 1g:20mL, cooled, taken out and dried to obtain glass slag; the glass slag was ground and passed through a 200-mesh sieve to obtain glass coarse powder; then 1 part of anhydrous ethanol and 1 part of the glass coarse powder were mixed evenly, ball-milled for 3 hours, and passed through a 350-mesh sieve to obtain a glass binder;

[0083] (3) By weight, 0.4 parts of glass binder, 0.3 parts of composite conductive material, 0.3 parts of organic vehicle, and 0.01 parts of Tween 85 were mixed, and stirred at a speed of 230 r / min for 20 min to obtain the thick film material for electronic components.

[0084] The organic solvent is prepared by mixing pinene alcohol, diethylene glycol butyl ether acetate and tributyl citrate in a mass ratio of 60:19:5.

[0085] The thickener is hydroxyethyl cellulose.

[0086] The ball mill adopts a zirconia ball milling jar, the ball milling medium is zirconia balls, and the ball-to-material ratio is 1:1.

[0087] The method for preparing the composite conductive material comprises the following steps:

[0088] S1: adding 10 parts of carbon nanotubes to 200 parts of 46wt% concentrated nitric acid by weight and ultrasonically treating for 10 minutes, then heating to 120°C and stirring at 180r / min for 4 hours, cooling, centrifuging, washing and drying to obtain acidified carbon nanotubes;

[0089] S2: Disperse 2 parts of acidified carbon nanotubes in 200 parts of water and ultrasonically treat for 0.5 h, then add 1 part of sodium starch octenyl succinate, and then react for 12 h at 40°C and a stirring speed of 450 r / min. After the reaction, filter with a microporous filter membrane with a pore size of 0.45 μm, wash and dry to obtain carbon nanotubes coated with sodium starch octenyl succinate;

[0090] S3: In parts by mass, 0.29 parts of sodium chloride, 5.5 parts of modifier, and 0.8 parts of carbon nanotubes coated with sodium starch octenyl succinate were added to 20 parts of ethylene glycol, and stirred at 280 r / min for 15 min. Then, 1.7 parts of silver nitrate were added, and stirring was continued at 280 r / min for 30 min. Then, the mixture was heated to 170°C at a rate of 10°C / min in a nitrogen atmosphere. Stirring and nitrogen introduction were stopped, and the reaction was continued for 1 hour. The mixture was cooled to room temperature in an ice bath, and a composite conductive material was obtained by centrifugation, washing, and drying.

[0091] The ultrasonic frequency in steps S1 and S2 is 50kHz and the power is 160W.

[0092] The modifier is nonylphenol polyoxyethylene ether.

[0093] Example 5

[0094] A method for preparing a thick film material for electronic components comprises the following steps:

[0095] (1) Preparation of an organic carrier: 84 parts of an organic solvent and 5 parts of a thickener were mixed uniformly by weight, heated to 90° C., and stirred at 180 r / min for 15 min, then 4 parts of castor oil were added, and the mixture was stirred at 90° C. and 180 r / min for 2 h, and then cooled to room temperature to obtain an organic carrier;

[0096] (2) Preparation of glass binder: 2.2 parts of calcium oxide, 1.4 parts of boron trioxide, 2.4 parts of silicon dioxide, and 6 parts of water were mixed by weight, ball-milled for 12 hours, taken out and dried, and then calcined at 1400°C for 2 hours to obtain molten glass liquid; the molten glass liquid was poured into water at a bath ratio of 1g:20mL, cooled, taken out and dried to obtain glass slag; the glass slag was ground and passed through a 200-mesh sieve to obtain glass coarse powder; then 1 part of anhydrous ethanol and 1 part of the glass coarse powder were mixed evenly, ball-milled for 3 hours, and passed through a 350-mesh sieve to obtain a glass binder;

[0097] (3) By weight, 0.4 parts of glass binder, 0.3 parts of composite conductive material, 0.3 parts of organic vehicle, and 0.01 parts of Tween 85 were mixed, and stirred at a speed of 230 r / min for 20 min to obtain the thick film material for electronic components.

[0098] The organic solvent is prepared by mixing pinene alcohol, diethylene glycol butyl ether acetate and tributyl citrate in a mass ratio of 60:19:5.

[0099] The thickener is hydroxyethyl cellulose.

[0100] The ball mill adopts a zirconia ball milling jar, the ball milling medium is zirconia balls, and the ball-to-material ratio is 1:1.

[0101] The method for preparing the composite conductive material comprises the following steps:

[0102] S1: adding 10 parts of carbon nanotubes to 200 parts of 46wt% concentrated nitric acid by weight and ultrasonically treating for 10 minutes, then heating to 120°C and stirring at 180r / min for 4 hours, cooling, centrifuging, washing and drying to obtain acidified carbon nanotubes;

[0103] S2: Disperse 2 parts of acidified carbon nanotubes in 200 parts of water and ultrasonically treat for 0.5 h, then add 1 part of sodium starch octenyl succinate, and then react for 12 h at 40°C and a stirring speed of 450 r / min. After the reaction, filter with a microporous filter membrane with a pore size of 0.45 μm, wash and dry to obtain carbon nanotubes coated with sodium starch octenyl succinate;

[0104] S3: In parts by mass, 0.29 parts of sodium chloride, 5.5 parts of modifier, and 0.8 parts of carbon nanotubes coated with sodium starch octenyl succinate were added to 20 parts of ethylene glycol, and stirred at 280 r / min for 15 min. Then, 1.7 parts of silver nitrate were added, and stirring was continued at 280 r / min for 30 min. Then, the mixture was heated to 170°C at a rate of 10°C / min in a nitrogen atmosphere. Stirring and nitrogen introduction were stopped, and the reaction was continued for 1 hour. The mixture was cooled to room temperature in an ice bath, and a composite conductive material was obtained by centrifugation, washing, and drying.

[0105] The ultrasonic frequency in steps S1 and S2 is 50kHz and the power is 160W.

[0106] The modifier is hexadecyltrimethylammonium chloride.

[0107] Test Example 1

[0108] Square resistance determination: refer to GB / T 17473.3-2008 "Test method for square resistance determination of precious metal paste for microelectronics technology". Sample preparation: Use a screen printer with an aperture of 74μm to print the special thick film material for electronic components prepared in each embodiment on an alumina ceramic substrate, dry at 120℃ for 15min, then place it at 800℃ for curing for 1h, and obtain a thick film resistor after cooling. The screen printing scraper angle is 75°, the printing pressure is 90N, and the printing speed is 180mm / s; the film width is 1mm and the length is 100mm. The above thick film resistor is placed in the test environment for 4h and then measured with a resistance meter.

[0109] Table 1: Square resistance measurement results

[0110] Square resistance (mΩ / □) Example 1 6.8 Example 2 5.6 Example 3 2.8 Example 4 3.1 Example 5 3.2

[0111] As can be seen from Table 1, Example 1 uses silver nanowires alone as a composite conductive material, and its square resistance is the largest, indicating that the electronic component-specific thick film material obtained in Example 1 has the worst conductivity, while Example 2 uses carbon nanotubes to load silver nanowires, and its square resistance is reduced. This is because the growth of silver nanowires is regulated by using carbon nanotubes as the substrate, so that the silver nanowires grow longitudinally along the carbon nanotubes, which improves the orderliness of the silver nanowires. After high-temperature curing, the carbon nanotubes disappear, and the silver nanowires are orderly arranged along the direction of the carbon nanotubes, and are connected to each other to form conductive chains. The chains are cross-linked to form a conductive network. Compared with directly adding silver nanowires, its dispersibility is better, the silver nanowires are longer, and the conductive network is more regular, thereby reducing the square resistance of the electronic component-specific thick film material obtained and improving its conductivity. The electronic component-specific thick film material obtained in Example 3 has the smallest square resistance after curing. This is because a strong oxidizing acid is used to open the carbon-carbon bond at the port or defect of the carbon nanotube, and to introduce active groups such as hydroxyl and carboxyl groups. Since nitric acid releases free oxygen atoms during the heating process, they combine with carbon atoms on the carbon nanotubes to form -C=O groups. At the same time, these free oxygen atoms combine with hydrogen ions and hydroxide ions in water, and have strong oxidizing properties. After oxidation, carboxyl groups can be formed on the surface of the carbon nanotubes. Then, the carboxyl groups are used as active sites to adsorb silver ions and realize the growth of silver nanowires on the surface of the carbon nanotubes. Its defects are obvious. There are fewer carboxyl groups on the surface of the carbon nanotubes and the silver loading is low. Therefore, the amount of silver responsible for conductivity in the composite conductive material prepared in Example 2 is less, and its resistance is slightly larger. In Example 3, the present invention further coats the carbon nanotubes with sodium starch glycolate. Since the surface of sodium starch glycolate glycolate contains a large number of carboxyl groups, it has a strong chelating effect on silver ions and can adsorb a large number of silver ions, greatly increasing the loading of nanosilver, thereby increasing the silver content in the composite conductive material prepared. Furthermore, due to the large number of silver ion adsorption sites on the surface of sodium starch octenyl succinate, the growth of silver nanowires is hindered. The present invention further uses nonylphenol polyoxyethylene ether and hexadecyl trimethyl ammonium chloride to regulate the growth direction of silver nanowires. Nonylphenol polyoxyethylene ether has a strong coating effect on silver nanowires, which controls the singleness of the growth direction of silver nanowires by coating, and hexadecyl dimethyl ammonium chloride also has the effect of chelating nanosilver, which can reduce the amount of silver ions on the surface of sodium starch octenyl succinate and control the rate of silver ion reduction. The two work synergistically to obtain a relatively regular silver nanowire on the surface of the carbon nanotube coated with sodium starch octenyl succinate, thereby improving its conductivity. The square resistance values ​​of Examples 4 and 5 are slightly greater than those of Example 3 because they only use nonylphenol polyoxyethylene ether or hexadecyl trimethyl ammonium chloride to regulate the growth of silver nanowires, making the silver nanowires grown on the surface of the carbon nanotube coated with sodium starch octenyl succinate more messy, affecting its dispersibility in the thick film material for electronic components.

[0112] Test Example 2

[0113] The porosity was measured using the Archimedes drainage method.

[0114] Sample preparation: The electronic component-specific thick film material prepared in each embodiment was printed on an alumina substrate using a screen printer with an aperture of 74 μm, dried at 120°C for 15 min, then cured at 800°C for 1 h, and cooled to obtain a thick film resistor. The screen printing scraper angle was 75°, the printing pressure was 90 N, and the printing speed was 180 mm / s; the film width was 1 mm and the length was 100 mm.

[0115] Put the sample in deionized water, heat it to 100℃, keep it warm for about 2h, cool it to room temperature, take out the sample, wipe the moisture on its surface, weigh it and record it as m3; tie the sample to the hair and put it in water, weigh it and record it as m2; put the sample in an oven at 100℃ and dry it for about 2h, take it out and cool it naturally to room temperature, weigh it and record it as m1; the specific calculation formula is as follows:

[0116] Porosity:

[0117]

[0118] Table 2: Porosity measurement results

[0119] Porosity / % Example 1 1.62 Example 2 1.83 Example 3 1.94

[0120] As can be seen from Table 2, the porosity of Example 2 is higher than that of Example 1. This is because the carbon nanotube content of the composite conductive material prepared in Example 2 is relatively large. During the high-temperature curing process, the carbon nanotubes are converted into gas and volatilized, causing the porosity of the film to increase. The content of carbon nanotubes in the composite conductive material prepared in Example 3 is lower than that in Example 2 because the content of nanowires is higher. However, after the high-temperature curing of the prepared thick film material for electronic components, the porosity is slightly increased. We believe that this is because the composite conductive material prepared in Example 3 is adsorbed by sodium octenyl succinate starch, nonylphenol polyoxyethylene ether and hexadecyl trimethyl ammonium chloride to obtain a better silver nanowire structure that is not easy to collapse. When the carbon nanotubes are volatilized, the silver nanowires form a hollow structure, which increases its porosity. This also proves the reason why the thick film material for electronic components prepared in Example 3 in Test Example 1 has the smallest square resistance after curing.

Claims

1. A method for preparing a thick film material for electronic components, characterized in that: The following steps are involved: (1) Preparation of organic carrier: Heat and stir the organic solvent and thickener until the thickener is completely dissolved, then add castor oil and stir evenly at constant temperature, cool to room temperature and store for future use; (2) Preparation of glass binder: Calcium oxide, boron trioxide, silicon dioxide and water are mixed and ball-milled, taken out and dried, and then calcined at high temperature to obtain molten glass liquid, the molten glass liquid is poured into water, cooled and dried to obtain glass slag, the glass slag is ball-milled and sieved to obtain glass binder; (3) Evenly mixing the glass binder, the composite conductive material, the organic carrier, and the surfactant to obtain the special thick film material for electronic components.

2. The method for preparing a thick film material for electronic components as claimed in claim 1, characterized in that: The following steps are involved: (1) Preparation of an organic carrier: 80-85 parts of an organic solvent and 4-6 parts of a thickener are mixed uniformly by weight, heated to 85-95° C., stirred at 160-200 r / min for 10-20 min, then 3-5 parts of castor oil are added, and the mixture is stirred at 85-95° C. and 160-200 r / min for 1-3 h, and then cooled to room temperature to obtain an organic carrier; (2) Preparation of glass binder: by weight, 2-3 parts of calcium oxide, 1-2 parts of boron trioxide, 2-3 parts of silicon dioxide, and 5-7 parts of water are mixed and ball-milled for 10-14 hours, taken out and dried, and then calcined at 1300-1500°C for 1-3 hours to obtain molten glass liquid; the molten glass liquid is poured into water, cooled, taken out and dried to obtain glass slag; the glass slag is ground and passed through a 180-250 mesh sieve to obtain glass coarse powder; then 1-2 parts of anhydrous ethanol and 1-2 parts of glass coarse powder are mixed evenly, ball-milled for 2-4 hours, and passed through a 300-400 mesh sieve to obtain a glass binder; (3) By weight, 0.1-0.5 parts of glass binder, 0.1-0.5 parts of composite conductive material, 0.1-0.5 parts of organic carrier, and 0.005-0.015 parts of surfactant are mixed, and stirred at a speed of 200-300 r / min for 15-30 min to obtain the thick film material for electronic components.

3. The method for preparing a thick film material for electronic components as claimed in claim 2, characterized in that: The organic solvent is one or a mixture of two or more of terpineol, diethylene glycol butyl ether acetate and tributyl citrate.

4. The method for preparing a thick film material for electronic components as claimed in claim 2, characterized in that: The thickener is one or a mixture of two or more of ethyl cellulose, hydroxyethyl cellulose and polyvinyl alcohol.

5. The method for preparing the thick film material for electronic components as claimed in claim 2, characterized in that: The surfactant is one of Tween 85 and Span.

6. The method for preparing the thick film material for electronic components according to claim 2, characterized in that: The ball mill adopts one of a zirconium oxide ball mill jar and a nylon ball mill jar.

7. The method for preparing the thick film material for electronic components as claimed in claim 2, characterized in that: The method for preparing the composite conductive material comprises the following steps: S1: adding 9-11 parts of carbon nanotubes to 180-210 parts of 40-60wt% concentrated nitric acid by weight, ultrasonically treating for 5-15 minutes, then heating to 110-130°C, stirring at 150-200r / min for 3-5 hours, cooling, centrifuging, washing and drying to obtain acidified carbon nanotubes; S2: Dispersing 1-3 parts of acidified carbon nanotubes in 180-220 parts of water by mass, ultrasonically treating for 0.5-1h, then adding 1-2 parts of sodium starch octenyl succinate, and then reacting at 35-45°C and a stirring speed of 400-500r / min for 10-14h. After the reaction, filtering with a microporous filter membrane with a pore size of 0.4-0.5μm, washing and drying to obtain carbon nanotubes coated with sodium starch octenyl succinate; S3: In parts by mass, 0.2-0.3 parts of sodium chloride, 5-6 parts of modifier, and 0.5-1 parts of carbon nanotubes coated with sodium starch octenyl succinate are added to 15-25 parts of ethylene glycol, and stirred at 200-300 r / min for 10-20 min, and then 1.5-2 parts of silver nitrate are added, and stirring is continued at 200-300 r / min for 20-40 min, and then heated to 160-180°C at a rate of 8-12°C / min in a nitrogen atmosphere, and stirring and nitrogen introduction are stopped. The reaction is continued for 1-2 hours, and the mixture is cooled to room temperature in an ice bath, and a composite conductive material is obtained by centrifugation, washing, and drying.

8. The method for preparing the thick film material for electronic components as claimed in claim 7, characterized in that: The modifier is one of nonylphenol polyoxyethylene ether and hexadecyl trimethyl ammonium chloride or a mixture of the two.

9. A thick film material for electronic components, characterized in that: Prepared by the method according to any one of claims 1 to 8.

10. Use of the special thick film material for electronic components as claimed in claim 9 in thick film electronic materials.

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