CN114927258A - Environment-friendly antioxidant conductive copper paste and preparation method and application thereof - Google Patents

Abstract

The invention relates to an environment-friendly antioxidant conductive copper paste and a preparation method thereof, wherein the conductive copper paste comprises the following raw materials in percentage by mass: copper powder 40-70 wt.%, organic binder 0.1-5 wt.%, bioreductive agent 3-10 wt.%, solvent 10-50 wt.%, and other additives 0.1-6 wt.%. The obtained environment-friendly anti-oxidation conductive copper paste can realize 180-fold low-temperature curing at 200 ℃, and after the copper paste product is stored for 45 days in the air atmosphere at room temperature, the volume resistivity of a copper wire or a copper film after sintering is still less than 5 multiplied by 10 ^‑5 Omega cm, the conductivity of the copper paste can still be compared with that of the copper paste on the market. The environment-friendly antioxidant conductive copper paste prepared by the invention is suitable for circuit printing in flexible devices or electronic element preparation, and the used raw materials are environment-friendly, pollution-free and non-toxic, and meet the requirement of green production.

Description

A kind of environment-friendly anti-oxidation conductive copper paste and its preparation method and application

technical field

The invention belongs to the field of material science and relates to a preparation method of conductive paste, in particular to an environment-friendly anti-oxidation conductive copper paste and a preparation method thereof.

Background technique

As an important functional material, conductive paste is widely used in metallurgy, chemical industry, electronic technology and other fields. The conductive paste is generally composed of three parts: conductive phase, binder phase and organic carrier. The conductive phase determines the basic properties of the conductive paste and affects the physical and mechanical properties of the paste product. The conductive phase is usually metal particles, alloy particles and their mixtures. The role of the binder phase is to make the conductive paste film layer and the base material firmly bonded, usually an organic binder or an inorganic binder, such as epoxy resin or a mixture of glass powder and oxide crystals. Mechanical and dielectric properties of films. The organic carrier is a mixture of organic polymers, surfactants, dispersants, thixotropic agents, etc. and solvents. It is the carrier of the conductive phase and the binder phase, which is used to wet and disperse the conductive phase particles and regulate the flow of the conductive paste. variable characteristics.

The conductive phase of the conductive paste is usually made of precious metal silver, gold, etc. Although they have excellent electrical conductivity and excellent oxidation resistance, the precious metal stock is small and the cost is high, and the metal silver particles are prone to electron migration effect during use. , resulting in poor product reliability. Metal copper is an ideal substitute material for preparing conductive paste. my country is rich in copper reserves, its price is much cheaper than silver and gold materials, and its conductivity is second only to silver. However, the chemical properties of copper are very active. It is easy to oxidize when exposed to the air at room temperature, and an oxide film is formed on its surface. The resistivity of the oxide film is large, and its electrical conductivity is reduced, which greatly reduces its practicality. The layer will greatly increase the heat treatment temperature of the conductive paste and increase the processing difficulty.

In the prior art, in order to prevent the oxidation of copper powder, the methods often used are: (1) silver or nickel plating on the surface of copper powder, silver or nickel is not easily oxidized in the air, and the copper is protected, but The uniformity and coverage of the coating on the surface of the copper powder after silver or nickel plating cannot be well guaranteed; (2) Add antioxidant components to the organic carrier, such as adding antioxidants or deoxidizers, antioxidants or deoxidizers before Copper powder is oxidized in contact with oxygen, reducing the chance of oxygen contacting copper powder. Antioxidant hydrazine hydrate is toxic, and deoxidizers such as phosphorus-containing organics, rare earth elements, etc., but adding phosphorus seriously reduces the conductivity of copper, making it lose As the function of electronic materials, the addition of rare earth elements has the problem of environmental pollution; (3) The organic polymer wraps the copper powder to form a protective shell on the surface of the copper powder to isolate oxygen, but the shell structure is easily broken during production and processing. , there is still a risk of being oxidized when exposed to air, and the required amount of surface coating agent is several times the volume of copper, which will cause a large volume shrinkage during sintering, and it is difficult to obtain a high-density sintered body, which will lead to changes in conductivity. (4) Using a reducing sintering atmosphere, such as hydrogen, the reducing gas is flammable and explosive, and how to effectively avoid the problem of gas leakage technically remains to be solved; (5) Add organic corrosion inhibitors to form protection on the surface of copper powder The coating, as a representative corrosion inhibitor such as imidazole compounds, can effectively prevent the oxidation of copper powder, but its heat resistance is poor. The formation of the surface oxide film greatly reduces the electrical conductivity; (6) the oxidation of copper powder is inhibited by low temperature sintering, this method can effectively solve the problem of oxidation of copper powder.

It is known that high temperature sintering is difficult to realize the application on resin substrates. For example, patent CN200810142382.6 weighs three kinds of mixed copper powder, glass powder and organic carrier with different particle sizes in proportion, and prepares copper paste by mixing, grinding and dispersing rolling. Although the invention obtains a copper film with good conductivity by sintering, the sintering peak temperature is as high as 700 °C. It is known that the glass transition temperature of most polymer materials is lower than 200 °C, while the commonly used PET and PI films are flexible The glass transition temperature of the substrate is in the range of 200-300 °C, so this technical solution is not suitable for flexible substrates, which will limit its application scenarios.

There are also reports on low-temperature sintered copper paste. For example, patent CN201710534066.2 reports an electronic paste based on low-melting metal micro-nano powder and its preparation method, using low-melting metal or alloy (melting point of -78-232°C) As a conductive phase to reduce the sintering temperature, but metals such as chromium and mercury are not environmentally friendly and are likely to cause environmental pollution; patent CN202110392854.9 uses copper paste particle size 1-20 μm to achieve low temperature curing at 180-300 ° C, but the phenyl glycidyl ether used Reagents such as cyclohexanone and cyclohexanone have toxic effects on the environment or human body, and are not environmentally friendly; patent CN201910315885.7 reports a low-temperature conductive copper paste and its preparation method, using silver-coated copper powder with a powder particle size of 5-15 μm, curing The temperature is high and cannot reach below 200 °C. In addition, there are often cracks on the surface of the silver-coated copper powder, which eventually leads to the oxidation of the copper core. The use of silver and the copper plating process also increase the cost of the conductive paste; patent CN201910727885.8 The low melting point SnAgCu alloy powder with a melting point of 218°C is added to the copper powder. The SnAgCu alloy powder melts and forms an intermetallic compound with the micron copper powder, which can be sintered and solidified at a low temperature of 180°C-250°C, but the alloy powder contains metallic silver, which increases the cost. , and the reducing agent sodium phosphate used is not environmentally friendly, and there is a risk of pollution.

In a word, the oxidation problem and low temperature heat treatment of copper powder limit its application in the field of conductive paste to a large extent. Therefore, it is necessary to develop an environmentally friendly and anti-oxidation conductive copper paste that can be sintered at 180-200 ° C. , so that it can be applied to a variety of substrate materials and broaden its application range.

SUMMARY OF THE INVENTION

In order to solve the technical problems existing in the prior art, one of the objectives of the present invention is to provide an environment-friendly anti-oxidation conductive copper paste, which can be sintered and solidified at a low temperature of 180-200° C. Excellent anti-oxidation and electrical conductivity, and the environment-friendly anti-oxidation conductive copper paste product is stored in room temperature air atmosphere for 45 days, the volume resistivity of copper wire or copper film after sintering is still less than 5×10 ^-5 Ω·cm, conductive The performance is better than most copper conductive pastes on the market.

The raw material composition of the environment-friendly anti-oxidation conductive copper paste is: copper powder 40-70wt.%, organic binder 0.1-5wt.%, biological reducing agent 3-10wt.%, other additives 0.1-6wt.%, solvent 10-50wt.%, and the added ratio of each raw material component is 100%.

According to an embodiment of the present invention, the biological reducing agent is capsaicin or one or more combinations of capsaicin and chitin, resveratrol, tannin, chlorogenic acid, caffeic acid, and piperine;

Preferably, the biological reducing agent is capsaicin, capsaicin:chitin=1:1 (mass ratio), capsaicin:resveratrol=1:1 (mass ratio), capsaicin:chlorogenic acid=1 : 1 (mass ratio), capsaicin: caffeic acid=1:1 (mass ratio);

Further, the capsaicin is trans-8-methyl-N-vanillyl-6-nonenamide, which is a colorless and odorless crystal powder with hydroxyl, methoxy, alkenyl in its molecular structure , amide group, adsorption interaction occurs between capsaicin and copper powder, the heteroatom and π bond in capsaicin can transfer electrons to the surface of copper powder, inhibit the oxidation of copper powder, play a role in corrosion inhibition, capsaicin molecular structure space Large steric hindrance, can protect and stabilize copper powder, and also play a certain role in dispersing copper powder;

Further, the chitin, resveratrol, tannic acid, chlorogenic acid, caffeic acid, and piperine all contain N, O heteroatoms, and all contain structures such as unsaturated bonds and hydroxyl groups, which can give electrons. It has a reducing effect, so that the prepared environment-friendly anti-oxidation conductive copper paste has anti-oxidation properties.

Preferably, the other additives include defoaming agents, thixotropic agents and dispersing agents; wherein,

The defoamer is a polyether defoamer or a silicone defoamer, and the polyether defoamer includes polyether defoamer GP-330, polyether defoamer GPE-3000 or polyether defoamer PPG -1000, silicone defoamer includes silicone defoamer FAG-470, silicone defoamer BYK-065, silicone defoamer BYK-066N or polysiloxane defoamer YCK-615; and defoamer The added amount of the agent accounts for 0.1-2wt.% of the environmentally friendly anti-oxidation conductive copper paste, and the function of the defoamer is to reduce air bubbles during the process of mixing and stirring the paste, so that the environmentally friendly copper conductive paste can be sintered during the sintering process. Reduce porosity, make sintering dense and reduce resistance;

The thixotropic agent is hydrogenated castor oil, oxidized polyethylene wax, polyamide wax, palm alcohol, Span-85 or ethylene glycol. -3wt.%; The function of the thixotropic agent is to make the slurry obtain the necessary thixotropy, when it is subjected to shearing force, it has fluidity, and when it is not subjected to shearing force, it restores the original state of the slurry; the amount of thixotropic agent added Too much will cause the environmentally friendly copper conductive paste to be difficult to remove during the sintering and curing process, and if too little is added, the thixotropic properties of the environmentally friendly copper conductive paste cannot be effectively provided.

The dispersant is amino clay or attapulgite clay, wherein the amino clay is a layered silicate, and the added amount of the dispersant accounts for 0.1-1 wt.% of the environment-friendly anti-oxidation conductive copper paste by mass;

Wherein, the amino clay is a self-made product, and the specific preparation method is as follows: dissolving magnesium chloride hexahydrate in 200 mL of absolute ethanol, fully stirring for 30 minutes, adding γ-aminopropyltriethoxysilane dropwise, and continuing to stir until the reaction is complete, The obtained white suspension was centrifuged at 5000rpm for 5min, then dried in a vacuum drying oven at 45°C for 24h, ground into powder and placed in a desiccator for use, wherein γ-aminopropyltriethoxysilane: magnesium chloride hexahydrate The amount ratio of the substances of 1.25-1.35 is 1.25-1.35, and the desired amino clay can be prepared within this ratio range; the structure of the amino clay is a layered structure, which can shield the oxygen in the air, and the amino group on the surface of the amino clay shows a reducing property. , can improve the oxidation resistance of copper in copper paste;

The attapulgite is a commercially available product, preferably a 1200-mesh attapulgite commercially available from Mingguang Tianke Minerals Co., Ltd. The attapulgite is gray-white and has internal porous channels. The heat dissipates during sintering, which reduces the sintering and curing temperature, and its surface also contains hydroxyl groups, which can play a certain anti-oxidation effect during the sintering process; amino clay or attapulgite not only has a dispersing effect due to its structural characteristics, but also has the ability to adjust the environmental protection type The role of viscosity of copper conductive paste.

The copper powder includes one or a combination of spherical copper powder, flake copper powder, dendritic copper powder, rod-shaped copper powder, fibrous copper powder or polyhedral copper powder,

Among them, the average particle size of spherical copper powder is 0.05-0.5μm, the average particle size of flake copper powder is 2-10μm, the average thickness is 0.05-0.2μm, the average particle size of dendritic copper powder is 3-5μm, rod-shaped The average diameter of the copper powder is 0.05-0.1 μm, the average length is 1-2.5 μm, the average diameter of the fibrous copper powder is 0.03-0.05 μm, the average length is 10-30 μm, and the average particle size of the polyhedral copper powder is 0.1-2 μm ;

Preferably, the copper powder can be spherical copper powder and flake copper powder in a mass ratio of 1:0.1-0.5, spherical copper powder and dendritic copper powder in a mass ratio of 1:0.1-0.5, spherical copper powder and rod-shaped copper powder in a mass ratio of 1:0.1-0.5 The mass ratio of copper powder is 1:0.1-0.5, the mass ratio of spherical copper powder and fibrous copper powder is 1:0.1-0.5, and the mass ratio of polyhedral copper powder and dendritic copper powder is 1:0.1-0.5; different shapes The copper powder compound can promote the effective contact and connection between the copper powders, and can ensure the conductivity of the environmentally friendly anti-oxidation conductive copper paste after sintering on the basis of reducing the amount of copper powder.

Preferably, the organic binder is polyvinyl alcohol resin (molecular weight 5000-10000), polyvinylpyrrolidone K-30 (molecular weight 44000-54000), polyethylene glycol-400, acrylic resin (molecular weight 5000-10000), Hydroxyethyl cellulose, hydroxypropyl cellulose, gelatin, shellac or gum arabic; the selected organic binder can enhance the decomposability of environmentally friendly anti-oxidative conductive copper paste during sintering, and obtain dense conductor paths with low resistance .

Preferably, the solvent is terpineol, carbitol, butyl carbitol, diethylene glycol ether acetate, dibutyl phthalate, tributyl citrate, ethylene glycol, propylene glycol, urethane One or more of ethylene glycol, diethylene glycol, triethylene glycol, diethylene glycol methyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, monoethanolamine, diethanolamine, and triethanolamine.

Another object of the present invention is to provide a preparation method of an environment-friendly anti-oxidation conductive copper paste. The present invention prepares the environment-friendly anti-oxidation conductive copper paste according to the following steps:

(1) Dissolving the organic binder in a solvent, adding a defoaming agent, a thixotropic agent and a dispersing agent, the heating temperature of the water bath is 30-60 ° C, stirring until completely dissolved, sieving and removing impurities to obtain an organic carrier;

(2) ultrasonically disperse the copper powder, the biological reducing agent and the solvent uniformly, then mix and disperse with the organic carrier to obtain a uniform first slurry; put the first slurry in a high-speed mixer or a planetary mixer Fully stirring and dispersing for 10-30min, and then rolling and dispersing 3-5 times in a three-roll mill. The slurry is finally filtered through a 5-10 μm filter to obtain an environmentally friendly anti-oxidation conductive copper slurry.

Wherein, the sieving in the step (1) is to use a 300-mesh stainless steel mesh or a polyester mesh to filter and remove impurities to ensure that the slurry is uniform and fine.

In the step (1), the amount of each component added in the organic carrier is as follows: organic binder: solvent: defoamer: thixotropic agent: dispersant = 0.1-8: 10-50: 0.1- 2: 0.1-3: 0.1-1.

In the step (2), the viscosity of the first slurry is controlled in the range of 15Pa·s-65Pa·s. If the viscosity is too large, the copper slurry will not be easily mixed evenly and the fluidity will be deteriorated, which will adversely affect the environmental protection type. If the viscosity of the oxidized conductive copper paste is too small, it will disadvantageously increase the shrinkage failure of the environmentally friendly anti-oxidation conductive copper paste when it is dried, and cannot form a dense conductive path, increase the resistance, and reduce the conductivity.

In addition, the present invention also claims to protect the application of the above-mentioned environmentally friendly anti-oxidation conductive copper paste in flexible devices.

Specifically, the application of the environment-friendly anti-oxidation conductive copper paste in circuit printing in flexible devices or preparation of electronic components.

Further, the environment-friendly anti-oxidation conductive copper paste prepared by the present invention is suitable for circuit printing in flexible devices or preparation of electronic components, and the raw materials used are environmentally friendly, non-polluting, non-toxic, and meet the requirements of green production.

Based on this, the present invention discloses an environment-friendly anti-oxidation conductive copper paste and its preparation method and application, which have the following advantages compared with the prior art:

(1) The environment-friendly anti-oxidation conductive copper paste prepared by the present invention can be sintered and solidified at a low temperature of 180-200° C., and has excellent oxidation resistance and electrical conductivity, and the environmentally-friendly anti-oxidation conductive copper paste product can be stored in an air atmosphere at room temperature. After 45 days of storage, the volume resistivity of the copper wire or copper film after sintering is still less than 5×10 ^-5 Ω·cm, and the electrical conductivity is better than most copper conductive pastes on the market;

(2) The present invention selects a biological reducing agent, and the heteroatoms (N, O) and π bonds in the biological reducing agent can transfer electrons to the surface of the copper powder, inhibit the oxidation of the copper powder, and play a role of corrosion inhibition. The capsaicin molecular structure space The steric hindrance is large, which can protect and stabilize the copper powder and play a dispersing role; the raw materials used are environmentally friendly and pollution-free.

(3) The present invention has the advantages of low cost and good volatility through self-made organic carrier, anti-oxidation sintering of environment-friendly anti-oxidation conductive copper paste can be realized under the protection of nitrogen atmosphere, the process for preparing environment-friendly anti-oxidation conductive copper paste is simple, and biological antioxidants Environmentally friendly and economical.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The invention provides an environment-friendly anti-oxidation conductive copper paste. The raw materials of the environment-friendly anti-oxidation conductive copper paste are calculated by mass percentage as follows: copper powder 40-70wt.%, organic binder 0.1-5wt.%, biological reduction 3-10 wt.% of additives, 0.1-6 wt.% of other additives, 10-50 wt.% of solvents, and the added ratio of each raw material component is 100%.

The prepared environmentally friendly anti-oxidation conductive copper paste was printed on an alumina ceramic substrate by screen printing technology, and then placed in a muffle furnace at 180°C for sintering and curing, and the resistivity of the obtained sample was tested by a four-point probe tester. .

The present invention is further described below in conjunction with specific embodiments, but does not limit the present invention.

Example 1

A preparation method of an environment-friendly anti-oxidation conductive copper paste, specifically comprising the following steps:

(1) Dissolving polyvinyl alcohol resin in carbitol, adding polyether defoamer GP-330, hydrogenated castor oil and amino clay, heating in a water bath at 60°C, stirring until completely dissolved, sieving through a screen to remove impurities , to obtain an organic carrier; the mass ratio of the components in the organic carrier is: organic binder: solvent: defoamer: thixotropic agent: dispersant = 5:38.5:1.5:1:1;

(2) Mix the spherical copper powder and the flake copper powder uniformly at a mass ratio of 1:0.4, wherein the average particle size of the spherical copper powder is 0.1-0.5 μm, and the average particle size of the flake copper powder is 2-10 μm, The average thickness is 0.05-0.2 μm, and it is uniformly dispersed with capsaicin and diethylene glycol ether acetate ultrasonically, and then mixed with an organic carrier and dispersed to obtain a uniform first slurry; put the first slurry in a high-speed mixer Fully stirring and dispersing for 30min, then rolling and dispersing in a three-roll mill for 5 times, the rolling speed is 400rpm, the rolling time is 4h, and the rolling fineness is less than 1μm to obtain the second slurry, which is finally filtered by 10μm. Mesh filtration to obtain environmentally friendly anti-oxidation conductive copper paste;

Wherein, the guaranteed amount of each component added in the environmentally friendly anti-oxidation conductive copper paste is: copper powder 45wt.%, organic binder 5wt.%, biological reducing agent 8wt.%, other additives 3.5wt.% %, solvent 38.5wt.%.

After storing the environmentally friendly anti-oxidation conductive copper paste product in an air atmosphere at room temperature for 45 days, the volume resistivity of the obtained copper film after sintering is 4.5×10 ^-5 Ω·cm as the average of three groups of parallel samples.

Example 2

A preparation method of an environment-friendly anti-oxidation conductive copper paste, specifically comprising the following steps:

(1) Dissolve polyvinylpyrrolidone K-30 in butyl carbitol, add polyether defoamer PPG-1000, polyamide wax and attapulgite clay, heat at a temperature of 55°C in a water bath, stir until completely dissolved, sieve The net is sieved to remove impurities to obtain an organic carrier; the mass ratio of each component in the organic carrier is: organic binder: solvent: defoamer: thixotropic agent: dispersant = 7:25:2:2:1 ;

(2) The mass ratio of spherical copper powder and dendritic copper powder is 1:0.5, the average particle size of spherical copper powder is 0.1-0.5 μm, the average particle size of dendritic copper powder is 3-5 μm, capsaicin: white Veratrol=1:1 (mass ratio) and butyl carbitol solvent ultrasonically dispersed uniformly, then mixed with an organic carrier and dispersed to obtain a uniform first slurry; fully stir the first slurry in a planetary mixer Disperse for 25min, and then roll and disperse 5 times in a three-roll mill. The rolling speed is 500rpm, the rolling time is 3.5h, and the rolling fineness is less than 1μm to obtain the second slurry, which is finally filtered through an 8μm filter. , to obtain environmentally friendly anti-oxidation conductive copper paste;

Wherein, the guaranteed addition amount of each component in the environment-friendly anti-oxidation conductive copper paste is: copper powder 53wt.%, organic binder 7wt.%, biological reducing agent 10wt.%, other additives 5wt.% , solvent 25wt.%.

After storing the environmentally friendly anti-oxidation conductive copper paste product in an air atmosphere at room temperature for 45 days, the volume resistivity of the obtained copper film after sintering is 4.1×10 ^-5 Ω·cm as the average of three groups of parallel samples.

Example 3

A preparation method of an environment-friendly anti-oxidation conductive copper paste, specifically comprising the following steps:

(1) Dissolve acrylic resin in ethylene glycol monoethyl ether, add silicone antifoaming agent FAG-470, oxidized polyethylene wax and amino clay, water bath heating temperature is 45 ℃, stir until completely dissolved, sieve through the screen to remove The organic carrier is obtained; the addition amount of each component in the organic carrier is: organic binder: solvent: defoamer: thixotropic agent: dispersant = 5:36:2:1.5:0.5;

(2) The spherical copper powder and the rod-like copper powder are uniformly dispersed by mass ratio of 1:0.5, capsaicin: chlorogenic acid=1:1 (mass ratio) and monoethanolamine solvent, and then mixed with an organic carrier and dispersed, Obtain a uniform first slurry; fully stir and disperse the first slurry in a planetary mixer for 30 minutes, and then roll and disperse it three times in a three-roll mill. The rolling speed is 500 rpm and the rolling time is 2 hours to ensure rolling. When the fineness is less than 1 μm, a second slurry is obtained, which is finally filtered through a 5 μm filter to obtain an environmentally friendly anti-oxidation conductive copper slurry;

Wherein, the guaranteed addition amount of each component in the environment-friendly anti-oxidation conductive copper paste is: copper powder 50wt.%, organic binder 5wt.%, biological reducing agent 5wt.%, other additives 4wt.% , solvent 36wt.%.

After storing the environmentally friendly anti-oxidation conductive copper paste product in an air atmosphere at room temperature for 45 days, the volume resistivity of the obtained copper film after sintering is 4.8×10 ^-5 Ω·cm as the average of three parallel samples.

Comparative Example 1

The difference between Comparative Example 1 and Example 1 is only that no biological reducing agent is added, and the others remain unchanged. The preparation steps of Comparative Example 1 to prepare an environmentally friendly anti-oxidative conductive copper paste are as follows:

(1) Dissolving polyvinyl alcohol resin in carbitol, adding polyether defoamer GP-330, hydrogenated castor oil and amino clay, heating in a water bath at 60°C, stirring until completely dissolved, sieving through a screen to remove impurities , to obtain an organic carrier; the mass ratio of the components in the organic carrier is: organic binder: solvent: defoamer: thixotropic agent: dispersant = 5:38.5:1.5:1:1;

(2) Mix the spherical copper powder and the flake copper powder uniformly at a mass ratio of 1:0.4, wherein the average particle size of the spherical copper powder is 0.1-0.5 μm, and the average particle size of the flake copper powder is 2-10 μm, The average thickness is 0.05-0.2 μm, and it is uniformly dispersed with capsaicin and diethylene glycol ether acetate ultrasonically, and then mixed with an organic carrier and dispersed to obtain a uniform first slurry; put the first slurry in a high-speed mixer Fully stirring and dispersing for 30min, then rolling and dispersing in a three-roll mill for 5 times, the rolling speed is 400rpm, the rolling time is 4h, and the rolling fineness is less than 1μm to obtain the second slurry, which is finally filtered by 10μm. Mesh filtration to obtain environmentally friendly anti-oxidation conductive copper paste;

Wherein, the guaranteed addition amount of each component in the environment-friendly copper paste is: copper powder 45wt.%, organic binder 5wt.%, other additives 3.5wt.%, solvent 38.5wt.%.

After storing the environment-friendly copper paste product in an air atmosphere at room temperature for 45 days, the volume resistivity of the copper film after sintering is 7.3 × 10 ^-5 Ω·cm, which is greater than the resistivity of the copper film in Example 1. Compared with the environment-friendly copper paste without capsaicin, the environment-friendly anti-oxidation conductive copper paste with capsaicin can effectively improve the antioxidant capacity, thereby improving the electrical conductivity.

Comparative Example 2

The difference between Comparative Example 2 and Example 1 is that the sintering temperature is different. The preparation of the copper paste in Comparative Example 1 is carried out according to the formula described in the patent CN109979686A, and the specific steps are as follows:

(1) get the solid macromolecular polyester resin with mass percentage of 45% and join it in the diethylene glycol ethyl ether acetate solvent of 65%, and obtain the macromolecular polyester resin carrier after dissolving;

(2) Take silver-coated copper powder with an average particle size of 5-15 μm, the silver-coated copper powder is in the form of flakes, and the silver-coated copper powder is 45% by mass percentage and the polymer polyester resin carrier described in step (1) is 52% Add it into the high-speed disperser, and the high-speed disperser disperses to obtain a preliminary uniform primary carrier, pours the carrier into a three-roller machine and grinds and disperses to obtain a secondary carrier. 1% was added to the planetary mixer and vacuumed to remove air bubbles to obtain conductive copper paste slurry.

After the conductive paste product containing silver-coated copper powder obtained in step (2) is stored in an air atmosphere at room temperature for 45 days, sintering and curing can be achieved at a temperature of 380 ° C, and the volume resistivity of the copper film after sintering is 2.6×10 ^-5 Ω· cm, and the composite copper powder with a smaller average particle size used in Example 1 of the present invention greatly reduces the sintering temperature, and can realize effective contact between copper powder and copper powder under the condition of reducing the amount of copper powder, and the present invention The biological reducing agent in the oxidizing agent has an effective anti-oxidation effect, and the obtained environmentally friendly anti-oxidizing conductive copper paste has strong anti-oxidative ability, resulting in low resistivity and good electrical conductivity of the obtained copper film product. The environmentally friendly anti-oxidation conductive copper paste prepared by the adopted technical solution formula has good stability and can be stored for a long time at room temperature for 10 months without delamination.

Based on the above analysis, it can be known that the embodiments 1-3 of the present invention are compared with Comparative Examples 1 and 2, and compared with the prior art solutions, the technical solutions of the present invention have the advantages of simple process, green environmental protection and high efficiency, and good anti-oxidation performance. It can realize the advantages of low temperature sintering and curing.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. an environment-friendly anti-oxidation conductive copper paste, characterized in that the raw materials of the environment-friendly anti-oxidation conductive copper paste are, by mass percentage: copper powder 40-70wt.%, organic binder 0.1-5wt.% , 3-10wt.% of biological reducing agent, 0.1-6wt.% of other additives, 10-50wt.% of solvent, and the added ratio of each raw material component is 100%. 2. a kind of environment-friendly anti-oxidation conductive copper paste according to claim 1, is characterized in that, described biological reducing agent is capsaicin or capsaicin and chitin, resveratrol, tannin, chlorogenic acid , one or more combinations of caffeic acid and piperine. 3. An environment-friendly anti-oxidation conductive copper paste according to claim 1, wherein the other additives include a defoamer, a thixotropic agent and a dispersant; wherein, The defoamer is a polyether defoamer or a silicone defoamer, and the defoamer accounts for 0.1-2wt.% of the environment-friendly anti-oxidation conductive copper paste by mass; The thixotropic agent is hydrogenated castor oil, oxidized polyethylene wax, polyamide wax, palm alcohol, Span-85 or ethylene glycol, and the thixotropic agent accounts for the mass percentage of the environment-friendly anti-oxidation conductive copper paste 0.1-3wt.%; The dispersant is amino clay or attapulgite clay, and the mass percentage of the dispersant in the environment-friendly anti-oxidation conductive copper paste is 0.1-1 wt.%; And, the preparation method of described amino clay is as follows: Dissolve magnesium chloride hexahydrate in 200 mL of absolute ethanol, stir fully for 30 min, add γ-aminopropyltriethoxysilane dropwise, continue stirring until the reaction is complete, centrifuge the obtained white suspension at 5000 rpm for 5 min, and then vacuum Dry in a drying oven at 45°C for 24 hours, grind into powder to obtain the amino clay, and put it in a desiccator for use; Wherein, the substance ratio of γ-aminopropyltriethoxysilane:magnesium chloride hexahydrate is 1.25-1.35. 4. a kind of environment-friendly anti-oxidation conductive copper paste according to claim 3, is characterized in that, described polyether defoamer is polyether defoamer GP-330, polyether defoamer GPE-3000 or Polyether defoamer PPG-1000, the silicone defoamer is silicone defoamer FAG-470, silicone defoamer BYK-065, silicone defoamer BYK-066N or polysiloxane defoamer agent YCK-615. 5. An environmentally friendly anti-oxidation conductive copper paste according to claim 1, wherein the copper powder is at least spherical copper powder, flake copper powder, dendritic copper powder, rod-shaped copper powder, and fibrous copper powder A kind of powder, polyhedral copper powder, of which, The average particle size of spherical copper powder is 0.05-0.5μm; the average particle size of flake copper powder is 2-10μm and the average thickness is 0.05-0.2μm; the average particle size of dendritic copper powder is 3-5μm; rod-shaped copper powder The average diameter of the copper powder is 0.05-0.1 μm and the average length is 1-2.5 μm; the average diameter of the fibrous copper powder is 0.03-0.05 μm and the average length is 10-30 μm; the average particle size of the polyhedral copper powder is 0.1-2 μm. 6. An environment-friendly anti-oxidation conductive copper paste according to claim 1, wherein the organic binder is polyvinyl alcohol resin, polyvinylpyrrolidone K-30, polyethylene glycol-400, acrylic acid Resin, hydroxyethyl cellulose, hydroxypropyl cellulose, gelatin, shellac or gum arabic. 7. A kind of environment-friendly anti-oxidation conductive copper paste according to claim 1, characterized in that, the solvent is at least terpineol, carbitol, butyl carbitol, diethylene glycol ether acetate, adjacent Dibutyl Phthalate, Tributyl Citrate, Ethylene Glycol, Propylene Glycol, Aminomethyl Propanol, Diethylene Glycol, Triethylene Glycol, Diethylene Glycol Methyl Ether, Ethylene Glycol Monomethyl Ether, Ethylene Glycol Mono One of ether, monoethanolamine, diethanolamine and triethanolamine. 8. A method for preparing an environmentally friendly anti-oxidation conductive copper paste according to any one of claims 1 to 7, wherein the method comprises the following steps: (1) Dissolve the organic binder in the solvent, add defoamer, thixotropic agent and dispersant, heat the water bath at a temperature of 30-60 °C, stir until completely dissolved, and filter with a 300-mesh stainless steel mesh or polyester mesh to remove The organic carrier is obtained; the addition amount of each component in the organic carrier is: organic binder: solvent: defoamer: thixotropic agent: dispersant = 0.1-8: 10-50: 0.1-2 : 0.1-3: 0.1-1; (2) ultrasonically disperse the copper powder, the biological reducing agent and the solvent uniformly, then mix and disperse with the organic carrier to obtain a uniform first slurry; control the viscosity of the first slurry to be 15Pa·s-65Pa s, fully stir and disperse the first slurry in a high-speed mixer or planetary mixer for 10-30min, and then roll and disperse it in a three-roll mill for 3-5 times. The rolling speed is 400-500rpm. The time is 2-5h to ensure that the rolling fineness is less than 1 μm, and the second slurry is obtained, which is finally filtered through a filter screen of 5-10 μm to obtain the environment-friendly anti-oxidation conductive copper slurry. 9 . The method for preparing an environment-friendly anti-oxidation conductive copper paste according to claim 8 , wherein the environment-friendly anti-oxidation conductive copper paste can be cured at a low temperature of 180-200° C., and the environment-friendly After the anti-oxidation conductive copper paste product is stored in an air atmosphere at room temperature for 45 days, the volume resistivity of the copper wire or copper film after sintering is still less than 5×10 ^-5 Ω·cm. 10 . The application of the environment-friendly anti-oxidation conductive copper paste according to claims 1 to 7 or the environment-friendly anti-oxidation conductive copper paste prepared by the method according to claim 8 in a flexible device. 11 .