Conductive adhesive and preparation method thereof, improved conductive paste composition and improved conductive paste

Abstract

The invention provides a conductive adhesive and a preparation method thereof, an improved conductive paste composition and improved conductive paste. In the structural formula I of the conductive adhesive, Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9 and Ar10 are respectively and independently selected from any one or more of arylene groups of C6-C12 and heteroarylene groups of C4-C12. The conductive adhesive has the structure, iron atoms with high conductivity are bonded into the chain segments of the conductive adhesive, the conductive adhesive can conduct current while playing a bonding role, the conductive adhesive is applied to the adhesive in low-temperature silver paste, additional conductive materials can be prevented from being added, about 50% of the adhesive can be added, and the cost is reduced. Therefore, the defect that the addition amount of the adhesive is small is avoided, and the low-temperature silver paste comprising the conductive adhesive can be taken into account at the same time. In addition, the cost can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of conductive paste, in particular to a conductive adhesive, a preparation method thereof, an improved conductive paste composition and an improved conductive paste. BACKGROUND

[0002] Low-temperature silver paste is an important electronic functional material, which is widely used in the fields of printed electronics, photovoltaics, flexible display, RFID, etc. Traditional low-temperature silver paste usually contains the following components: silver powder as the conductive phase (about 59% to 80%), pure organic polymer resin as the binder phase, solvent and various additives (such as leveling agent, thixotropic agent, etc.). The resin matrix is an important component of low-temperature conductive silver paste, which plays a role in bonding and supporting silver powder particles. The selection and amount of the resin matrix have an important influence on the conductive performance of the low-temperature conductive silver paste. Traditional resins mainly include epoxy, polyester, ethyl cellulose, etc.

[0003] Defects of prior art:

[0004] There is a clear game effect between the stability and conductivity of silver paste: the traditional binder (adhesive) is usually an insulator and has no conductive sites. If the amount of the binder is too much, although the storage stability of the paste and the adhesion after film formation are improved, too much organic binder will form too much insulating residue, hinder the conductive contact between silver powder, restrict the transfer of photo-generated carriers, significantly reduce the connectivity of the conductive channel, cause the paste resistivity to rise and the conductive performance to deteriorate, and seriously affect the conductivity of the paste after curing. On the contrary, if the amount of the adhesive is too small (usually controlled at 15 to 20%), although the electrical conductivity can be maintained, the adhesion and support of the silver powder are not enough, and the paste is prone to stability problems such as sedimentation and flocculation, and the mechanical properties (such as adhesion and weather resistance) after film formation are poor. The main solution to this problem is to add conductive materials such as graphite to the resin and silver powder formulation, which increases the cost and complicates the process.

[0005] High silver content and cost: Silver powder, as a precious metal, is the main source of paste cost. To obtain high electrical conductivity, a very high silver content (usually >80%) must be maintained, resulting in high cost.

[0006] Complex preparation process: The synthesis of traditional adhesives often uses acid-base catalysts, and after the reaction is completed, a tedious purification step is needed to remove impurity ions, otherwise these ions will corrode the silver powder and affect the long-term reliability of the paste

[0007] High-temperature curing and process limitations: In order to achieve sufficient crosslinking and stable adhesion of the resin, many traditional low-temperature silver pastes require curing temperatures of 150 to 200℃, which limits their application on flexible plastic substrates with poor heat resistance.

[0008] In summary, in the traditional low-temperature silver paste, the adhesive is an insulating material, and the addition amount of the adhesive can improve the stability of the silver paste. Due to the blocking of the adhesive to the silver powder, the tunnel effect of the photo-generated electron conduction is blocked, and the conductivity of the cured silver paste is obviously reduced. If the addition amount of the adhesive is insufficient, the long-term stability of the cured silver paste system is insufficient, the contact between the silver powder particles is insufficient, and the conductivity is reduced due to the influence of percolation. SUMMARY

[0009] The main purpose of the present application is to provide a conductive adhesive and a preparation method thereof, an improved conductive paste composition and an improved conductive paste, so as to solve the problem that the adhesive in the prior art is difficult to balance high stability and high conductivity.

[0010] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a conductive adhesive is provided, which has the following structural formula I:

[0011]

[0012] Among them, Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10 Each is independently selected from any one or more of C6-C 12 arylene, C4-C 12 heteroarylene.

[0013] Further, Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10 Each is independently selected from any one or more of C6-C 10 arylene, C4-C 10 heteroarylene; preferably, Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10 Each is independently selected from any one or more of The dotted line in them represents the connection position of these groups in structural formula I.

[0014] Further, the weight average molecular weight of the conductive adhesive is 16-42 thousand, and / or the glass transition temperature of the conductive adhesive is 100-150℃; and / or the room temperature adhesion of the conductive adhesive is 30-45MPa; and / or the thermal stability temperature of the conductive adhesive is 300-500℃.

[0015] According to another aspect of the present application, there is provided a method for preparing the aforementioned conductive adhesive, the method comprising: mixing raw materials comprising a hydroxyl-substituted aryl boronic acid and / or a hydroxyl-substituted heteroaryl boronic acid, dibromodiferrocene, a first acid-binding agent, a tetrakis triphenylphosphine palladium catalyst, and a first solvent, and then performing a first Suzuki coupling reaction in a nitrogen atmosphere to obtain a hydroxyl-substituted aryl dicyclopentadiene and / or a hydroxyl-substituted heteroaryl dicyclopentadiene; mixing raw materials comprising the hydroxyl-substituted aryl dicyclopentadiene and / or the hydroxyl-substituted heteroaryl dicyclopentadiene, chloromethyl-substituted oxirane, a strong base catalyst, and a second solvent, and then performing a nucleophilic substitution reaction to obtain a conductive adhesive component A; mixing raw materials comprising an amino-substituted aryl boronic acid and / or an amino-substituted heteroaryl boronic acid, dibromodiferrocene, a second acid-binding agent, a tetrakis triphenylphosphine palladium catalyst, and a third solvent, and then performing a second Suzuki coupling reaction in a nitrogen atmosphere to obtain a conductive adhesive component B; and mixing raw materials comprising the conductive adhesive component A and the conductive adhesive component B, and then curing to obtain the conductive adhesive.

[0016] Further, the temperature for curing is ≤ 150 °C, preferably 80-100 °C.

[0017] Further, the first solvent and the third solvent are each independently selected from any one or more of dioxane, toluene, and tetrahydrofuran; and / or, the first acid-binding agent and the second acid-binding agent are each independently selected from any one or more of sodium carbonate, potassium carbonate, and cesium carbonate; and / or, the temperature for the first Suzuki coupling reaction and the second Suzuki coupling reaction is each independently 60-120 °C, and the time is each independently 5-24 h; and / or, the hydroxyl-substituted aryl boronic acid is selected from any one or more of a hydroxyl phenyl boronic acid, a hydroxyl biphenyl boronic acid, and a hydroxyl naphthalene boronic acid; and / or, the hydroxyl-substituted heteroaryl boronic acid is selected from any one or more of a hydroxyl pyridyl boronic acid, a hydroxyl bipyridyl boronic acid, a hydroxyl thiophene boronic acid, a hydroxyl furan boronic acid, and a hydroxyl pyrrole boronic acid; and / or, the amino-substituted aryl boronic acid is selected from any one or more of an amino phenyl boronic acid, a p-amino biphenyl boronic acid, and an amino naphthalene boronic acid; and / or, the amino-substituted heteroaryl boronic acid is selected from any one or more of an amino pyridyl boronic acid, an amino bipyridyl boronic acid, an amino thiophene boronic acid, an amino furan boronic acid, and an amino pyrrole boronic acid.

[0018] Further, the second solvent is selected from any one or more of N,N-dimethylformamide, N-methyl pyrrolidone, N,N-dimethylacetamide, and dimethyl sulfoxide; and / or, the strong base catalyst is selected from any one or more of sodium hydroxide, potassium hydroxide, and ammonium hydroxide; and / or, the temperature for the nucleophilic substitution reaction is 80-120 °C, and the time is 8-24 h.

[0019] According to another aspect of the present application, there is provided an improved conductive paste composition, the improved conductive paste composition comprising, in mass percentage: 30-50% of conductive metal powder, 45-55% of binder phase, 1-15% of fourth solvent, and 0.1-2% of additive; wherein the binder phase is the conductive adhesive or is prepared by the preparation method.

[0020] Further, the additive comprises 0.05-0.09% of leveling agent and 1.3-1.5% of thixotropic agent; and / or the fourth solvent is selected from any one or more of ethyl acetate, acetone, methanol, ethanol, ethylene glycol ethyl ether, isopropyl alcohol, terpineol, and diethylene glycol butyl ether.

[0021] According to another aspect of the present application, there is provided an improved conductive paste, raw materials of the improved conductive paste comprising the improved conductive paste composition as described above, the improved conductive paste being cured at a temperature lower than 100°C to form an electrode.

[0022] Further, the improved conductive paste has an electrical conductivity of 1x10 4 -1x10 7 S / m, and / or a thermal expansion coefficient of 3.0x10 -6 / ℃-7.0x10 -6 / ℃.

[0023] By applying the technical solution of the present application, the conductive adhesive of the present application has the above structure, which bonds iron atoms with high conductivity into the chain segments of the conductive adhesive, the conductive adhesive can conduct current while playing a bonding role, and when the conductive adhesive is used in the adhesive of low-temperature silver paste, the addition of additional conductive materials can be avoided, and about 50% of the adhesive can be added, thereby avoiding the defect of small amount of adhesive, and thus the low-temperature silver paste comprising the conductive adhesive of the present application can be simultaneously considered. In addition, it is helpful to reduce the cost. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application, and do not constitute an improper limitation of the present application. In the drawings:

[0025] Figure 1 A nuclear magnetic hydrogen spectrum of a component of the conductive adhesive A in Example 1 according to the present application is shown.

[0026] Figure 2 A nuclear magnetic hydrogen spectrum of a component of the conductive adhesive B in Example 1 according to the present application is shown.

[0027] Figure 3 An infrared spectrum of the conductive adhesive in Example 1 according to the present application is shown.

[0028] Figure 4 A thermogravimetric analysis diagram of the conductive adhesive in Example 1 according to the present application is shown;

[0029] Figure 5 A SEM diagram of the conductive adhesive in Example 1 according to the present application is shown;

[0030] Figure 6 An action schematic diagram of the adhesive in Example 1 according to the present application in silver paste is shown;

[0031] Figure 7 An action schematic diagram of the ordinary adhesive in Comparative Example 1 in silver paste is shown. DETAILED DESCRIPTION

[0032] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] As analyzed in the background art of the present application, there is a problem in the prior art that the adhesive is difficult to balance high stability and high conductivity. In order to solve this problem, the present application provides a conductive adhesive and a preparation method thereof, an improved conductive paste composition and an improved conductive paste.

[0034] In a typical embodiment of the present application, a conductive adhesive is provided, which has the following structural formula I:

[0035]

[0036] wherein Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10 are each independently selected from any one or more of C6-C 12 arylene, C4-C 12 heteroarylene.

[0037] The conductive adhesive of the present application has the above structure, which bonds iron atoms with high conductivity into the chain segment of the conductive adhesive. The conductive adhesive can conduct current while playing a bonding role. When it is used as an adhesive in low-temperature silver paste, the addition of additional conductive materials can be avoided, and about 50% of the adhesive can be added, thereby avoiding the defect of small amount of adhesive addition, and thus the low-temperature silver paste including the conductive adhesive of the present application can be balanced at the same time. In addition, it is helpful to reduce the cost.

[0038] In some embodiments of the present application, the above Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10Each was independently selected from C6 to C6. 10 aryl, C4-C 10 Any one or more of the heteroaryl groups; preferably, Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10 Each independently selected

[0039] Any one or more of the groups, where the dashed lines indicate the connection positions of these groups in structural formula I.

[0040] The preferred types of substituents help to enrich the conductive sites of the conductive adhesive, thereby reducing the amount of silver powder used in traditional low-temperature silver paste, maintaining high conductivity while improving the long-term stability of the silver paste.

[0041] In some embodiments of this application, the weight-average molecular weight of the conductive adhesive is 16,000 to 42,000, and / or the glass transition temperature of the conductive adhesive is 100 to 150°C; and / or the room temperature adhesion of the conductive adhesive is 30 to 45 MPa; and / or the thermal stability temperature of the conductive adhesive is 300 to 500°C.

[0042] The preferred conductive adhesives with the above-mentioned structures possess the above-mentioned physicochemical properties, such as high molecular weight providing excellent mechanical properties, high glass transition temperature ensuring the silver paste system can work at high temperatures, room temperature adhesion ensuring reliable "temporary fixation" before high-temperature curing, ensuring smooth production processes, and thermal stability temperature helping to ensure that the conductive silver paste avoids irreversible degradation of its physicochemical and electrical properties when subjected to high-temperature processes and high-temperature environments.

[0043] In another typical embodiment of this application, a method for preparing the aforementioned conductive adhesive is provided. This method includes: in a nitrogen atmosphere, mixing raw materials comprising hydroxylated arylboronic acid and / or hydroxylated heteroarylboronic acid, ferrocene dibromo, a first acid-binding agent, a tetra-triphenylphosphine palladium catalyst, and a first solvent, and then performing a first Suzuki coupling reaction to obtain hydroxylated aryl ferrocene and / or hydroxylated heteroaryl ferrocene; mixing raw materials comprising hydroxylated aryl ferrocene and / or hydroxylated heteroaryl ferrocene, chloromethyl-substituted ethylene oxide, a strong base catalyst, and a second solvent, and then performing a nucleophilic substitution reaction to obtain conductive adhesive component A; in a nitrogen atmosphere, mixing raw materials comprising amino-substituted arylboronic acid and / or amino-substituted heteroarylboronic acid, ferrocene dibromo, a second acid-binding agent, a tetra-triphenylphosphine palladium catalyst, and a third solvent, and then performing a second Suzuki coupling reaction to obtain conductive adhesive component B; and mixing raw materials comprising conductive adhesive component A and conductive adhesive component B and then curing to obtain the conductive adhesive.

[0044] The principle of the reaction of the conductive adhesive A component and the conductive adhesive B component is as follows: the amino group in the conductive adhesive B component as an electron-rich nucleophile, the epoxy in the conductive adhesive A component is subjected to ring-opening addition reaction, and the conductive adhesive containing polar groups such as secondary hydroxyl and tertiary amine groups is obtained. The adsorption and adhesion of these polar groups to silver powder is strong. Since the conductive adhesive A component and the conductive adhesive B component have high iron content, the iron can fill the gaps between the silver powder, and a continuous carrier channel is formed, thereby maintaining the stability of the silver paste system and improving the electrical conductivity.

[0045]

[0046] In some embodiments of the present application, the temperature of the curing is ≤ 150℃, preferably 80-100℃.

[0047] The reaction of the conductive adhesive A component and the conductive adhesive B component is preferably initiated at the above lower temperature to obtain the conductive adhesive.

[0048] In some embodiments of the present application, the first solvent and the third solvent are each independently selected from any one or more of dioxane, toluene and tetrahydrofuran; and / or the first acid-binding agent and the second acid-binding agent are each independently selected from any one or more of sodium carbonate, potassium carbonate and cesium carbonate; and / or the temperature of the first Suzuki coupling reaction and the second Suzuki coupling reaction is each independently 60-120℃, and the time is each independently 5-24h; and / or the hydroxyl-substituted aryl boronic acid is selected from any one or more of hydroxyphenyl boronic acid, hydroxydiphenyl boronic acid and hydroxynaphthalene boronic acid; and / or the hydroxyl-substituted heteroaryl boronic acid is selected from any one or more of hydroxypyridyl boronic acid, hydroxybipyridyl boronic acid, hydroxythiophene boronic acid, hydroxyfuran boronic acid and hydroxypyrrole boronic acid; and / or the amino-substituted aryl boronic acid is selected from any one or more of aminophenyl boronic acid, p-aminodiphenyl boronic acid and aminonaphthalene boronic acid; and / or the amino-substituted heteroaryl boronic acid is selected from any one or more of aminopyridyl boronic acid, aminobipyridyl boronic acid, aminothiophene boronic acid, aminofuran boronic acid and aminopyrrole boronic acid.

[0049] The preferred reaction conditions and reaction raw materials above help to improve the reaction efficiency and effect of the first Suzuki coupling reaction and the second Suzuki coupling reaction.

[0050] In some embodiments of the present application, the second solvent is selected from any one or more of N,N-dimethylformamide, N-methylpyrrolidone, N,N-dimethylacetamide and dimethyl sulfoxide; and / or the strong base catalyst is selected from any one or more of sodium hydroxide, potassium hydroxide and ammonium hydroxide; and / or the temperature of the nucleophilic substitution reaction is 80-120℃, and the time is 8-24h.

[0051] The preferred second solvent, the strong base catalyst, and the temperature and time of the nucleophilic substitution reaction help to improve the reaction efficiency of the nucleophilic substitution reaction.

[0052] In another typical embodiment of the present application, an improved conductive paste composition is provided, which comprises, in percentage by mass: 30-50% of conductive metal powder, 45-55% of binder phase, 1-15% of fourth solvent, and 0.1-2% of additive; wherein the binder phase is the conductive adhesive described above or prepared by the preparation method described above.

[0053] The addition of silver powder mainly provides a channel for photo-generated carriers, which is conducive to current collection. Controlling the amount of silver powder helps to save costs. The addition of the binder phase is conducive to connecting silver particles to each other to enhance conductivity, and is conducive to firmly attaching the solidified silver paste to the battery piece. Controlling the amount of the binder phase is to enhance the stability of the conductive paste system and to enhance the electrical conductivity of the system.

[0054] In some embodiments of the present application, the additive described above comprises 0.05-0.09% of leveling agent and 1.3-1.5% of thixotropic agent; and / or the fourth solvent is selected from any one or more of ethyl acetate, acetone, methanol, ethanol, ethylene glycol ethyl ether, isopropyl alcohol, terpineol, and diethylene glycol butyl ether.

[0055] The addition of the leveling agent makes the conductive paste system more smooth, and the thixotropic agent makes the shape retention of the printed silver paste better. The preferred conductive paste system is conducive to promoting the uniform dispersion of each component in the improved conductive paste composition.

[0056] In another typical embodiment of the present application, an improved conductive paste is provided, the raw material of which comprises the improved conductive paste composition described above, and the improved conductive paste is solidified at a temperature lower than 100℃ to form an electrode.

[0057] The improved conductive paste not only takes into account the improved conductive paste, but also can be solidified at a temperature lower than 100℃ to achieve the effect of high-temperature solidification in ordinary silver paste, realizing sufficient crosslinking and stable adhesion of the resin.

[0058] In some embodiments of the present application, the electrical conductivity of the improved conductive paste described above is 1x10 4 -1x10 7 S / m, and / or the thermal expansion coefficient of the improved conductive paste is 3.0x10 -6 / ℃-7.0x10 -6 / ℃.

[0059] The improved conductive paste comprising the conductive adhesive of the present application has both the above excellent electrical conductivity and thermal expansion coefficient.

[0060] The beneficial effects of the present application are further illustrated below in combination with examples and comparative examples.

[0061] Example 1

[0062] 1,1'-dibromoferrocene (5 g, 0.0145 mol), p-hydroxybenzoic acid (4 g, 0.029 mol), potassium carbonate (2 g, 0.014 mol) and 0.2 g of tetrakis triphenylphosphine palladium were placed in a round bottom flask with a capacity of 250 mL equipped with a magnetic bar. 50 mL of dioxane was added, stirred and dissolved, replaced with nitrogen bubbling for five minutes, the temperature was raised to 80°C, and the reaction was carried out under nitrogen protection for 10 h. After the reaction was completed, it was cooled to room temperature, extracted with dichloromethane three times, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation to obtain the product 1,1'-(di-p-hydroxyphenyl)ferrocene with a yield of 87%. The above product 1,1'-(di-p-hydroxyphenyl)ferrocene (5 g, 0.0135 mol), epichlorohydrin (2.5 g, 0.027 mol) and 1 g of sodium hydroxide were placed in a 100 mL three-necked round bottom flask, 50 mL of N,N-dimethylformamide was added, and the reaction was carried out at 80°C for 8 h. After cooling to room temperature, the reaction was poured into 100 mL of water, and the conductive adhesive A component was obtained by suction filtration with a yield of 89%. Its nuclear magnetic hydrogen spectrum is shown in Figure 1 , wherein 2 ppm can be attributed to the hydrogen of methylene, 5 ppm can be attributed to the hydrogen on the epoxy group, and 6.8-7.3 ppm can be attributed to the hydrogen on the cyclopentadiene ring and benzene ring.

[0063] 1,1'-dibromoferrocene (5 g, 0.0145 mol), p-aminobenzoic acid (4 g, 0.029 mol), potassium carbonate (2 g, 0.014 mol) and 0.2 g of tetrakis triphenylphosphine palladium were placed in a round bottom flask with a capacity of 250 mL equipped with a magnetic bar. 50 mL of dioxane was added, stirred and dissolved, replaced with nitrogen bubbling for five minutes, the temperature was raised to 80°C, and the reaction was carried out under nitrogen protection for 10 h. After the reaction was completed, it was cooled to room temperature, extracted with dichloromethane three times, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation to obtain the product 1,1'-(di-p-hydroxyphenyl)ferrocene with a yield of 87%. The above product 1,1'-(di-p-hydroxyphenyl)ferrocene (5 g, 0.0135 mol), epichlorohydrin (2.5 g, 0.027 mol) and 1 g of sodium hydroxide were placed in a 100 mL three-necked round bottom flask, 50 mL of N,N-dimethylformamide was added, and the reaction was carried out at 80°C for 8 h. After cooling to room temperature, the reaction was poured into 100 mL of water, and the conductive adhesive A component was obtained by suction filtration with a yield of 89%. Its nuclear magnetic hydrogen spectrum is shown in Figure 2 , wherein 2 ppm can be attributed to the hydrogen of methylene, 5 ppm can be attributed to the hydrogen on the epoxy group, and 6.8-7.3 ppm can be attributed to the hydrogen on the cyclopentadiene ring and benzene ring.

[0064] The conductive adhesive A component was mixed with the conductive adhesive B component, and the conductive adhesive was obtained after curing at 100°C. Its infrared spectrum is shown in Figure 3 , wherein 3400 cm -1 the peaks can be attributed to the stretching vibration peak of hydroxyl; 1400-1700 cm-1 the series of peaks belong to the skeleton vibration peaks of benzene ring; 1363 cm -1 the peak at 1300 cm -1 the peak at 1257 cm -1 the peak at 1257 cm Figure 4 The thermal gravimetric analysis diagram is shown in Figure 2, and the stability is up to 500℃, and the thermal weight loss is only about 5%; the SEM diagram is shown in Figure 3. Figure 5

[0065] Comparative Example 1

[0066] An EP301 adhesive (Lianzhong Electronics Technology Co., Ltd.).

[0067] Application Example 1

[0068] The 50% conductive adhesive in Example 1 is mixed with 40% silver powder, 8.5% diethylene glycol butyl ether, 0.05% polyacrylic acid, and 1.45% white carbon black to obtain an improved conductive silver paste, and the schematic diagram of its role in the silver paste is shown in Figure 4. After curing at 80℃, an electrode is obtained. Figure 6

[0069] Application Comparative Example 1

[0070] The 30% EP301 adhesive in Comparative Example 1 is mixed with 60% silver powder, 8.5% diethylene glycol butyl ether, 0.05% polyacrylic acid, and 1.45% white carbon black to obtain an improved conductive silver paste, and the schematic diagram of its role in the silver paste is shown in Figure 5. After curing at 200℃, an electrode is obtained. Figure 7

[0071] Performance Test:

[0072] Weight average molecular weight: GPC method (gel permeation chromatography test).

[0073] Glass transition temperature: DSC (differential scanning calorimetry).

[0074] Electrical conductivity: electrical conductivity tester.

[0075] Thermal expansion coefficient: TMA static thermal mechanical analysis method.

[0076] Room temperature adhesion: CB T 7124-2008.

[0077] Thermal stability temperature: TGA (thermogravimetric analyzer).

[0078] The test data of the adhesives in Example 1 and Comparative Example 1 are listed in Table 1, and the test data of the improved conductive silver paste in Application Example 1 and Application Comparative Example 1 are listed in Table 2. ​​​

[0079] Table 1

[0080]

[0081] Table 2

[0082]

[0083] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0084] The conductive adhesive of the present application has the above structure, which bonds iron atoms with high conductivity into the chain segments of the conductive adhesive, and the conductive adhesive can conduct current while playing a bonding role. When the conductive adhesive is used in low-temperature silver paste, the addition of additional conductive materials can be avoided, and about 50% of the adhesive can be added, thereby avoiding the defect of small amount of adhesive addition, and further enabling the low-temperature silver paste including the conductive adhesive of the present application to be compatible at the same time. In addition, it is helpful to reduce the cost.

[0085] The above is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An electrically conductive adhesive, characterized by, The conductive adhesive has the following structural formula I: wherein Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10 each independently is selected from any one or more of C6-C 12 arylene, C4-C 12 heteroarylene.

2. The electrically conductive adhesive of claim 1, wherein The Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, and Ar 10 Each was independently selected from C6 to C6. 10 aryl, C4-C 10 Any one or more of the heteroaryl groups; preferably, Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, and Ar... 10 Each independently selected Any one or more of the groups, where the dashed lines indicate the connection positions of these groups in the structural formula I.

3. The electrically conductive adhesive of claim 1, wherein The weight average molecular weight of the conductive adhesive is 16-42 thousand, and / or the glass transition temperature of the conductive adhesive is 100-150℃; and / or the room temperature adhesion of the conductive adhesive is 30-45 MPa; and / or the thermal stability temperature of the conductive adhesive is 300-500℃.

4. A method of producing the electroconductive adhesive according to any one of claims 1 to 3, characterized by, The preparation method comprises: In a nitrogen atmosphere, raw materials including hydroxyl-substituted aryl boronic acid and / or hydroxyl-substituted heteroaryl boronic acid, dibromodiference, a first acid-binding agent, a tetraphenylphosphonium palladium catalyst and a first solvent are mixed to perform a first Suzuki coupling reaction to obtain hydroxyl-substituted aryl diphosphine and / or hydroxyl-substituted heteroaryl diphosphine; Raw materials including the hydroxyl-substituted aryl diphosphine and / or the hydroxyl-substituted heteroaryl diphosphine, chloromethyl-substituted oxirane, a strong base catalyst and a second solvent are mixed to perform a nucleophilic substitution reaction to obtain a conductive adhesive A component; In a nitrogen atmosphere, raw materials including amino-substituted aryl boronic acid and / or amino-substituted heteroaryl boronic acid, dibromodiference, a second acid-binding agent, a tetraphenylphosphonium palladium catalyst and a third solvent are mixed to perform a second Suzuki coupling reaction to obtain a conductive adhesive B component; The raw materials including the conductive adhesive A component and the conductive adhesive B component are mixed to obtain the conductive adhesive after curing.

5. The preparation method according to claim 4, characterized in that, The curing temperature is ≤150℃, preferably 80-100℃.

6. The production method according to claim 4 or 5, characterized by, The first solvent and the third solvent are each independently selected from any one or more of dioxane, toluene and tetrahydrofuran; And / or, the first acid-binding agent and the second acid-binding agent are each independently selected from any one or more of sodium carbonate, potassium carbonate and cesium carbonate; And / or, the temperature of the first Suzuki coupling reaction and the second Suzuki coupling reaction is each independently 60-120℃, and the time is each independently 5-24h; And / or, the hydroxyl-substituted aryl boronic acid is selected from any one or more of hydroxyl phenyl boronic acid, hydroxyl biphenyl boronic acid and hydroxyl naphthalene boronic acid; And / or, the hydroxyl-substituted heteroaryl boronic acid is selected from any one or more of hydroxyl pyridyl boronic acid, hydroxyl bipyridyl boronic acid, hydroxyl thiophene boronic acid, hydroxyl furan boronic acid and hydroxyl pyrrole boronic acid; And / or, the amino-substituted aryl boronic acid is selected from any one or more of amino phenyl boronic acid, p-amino biphenyl boronic acid and amino naphthalene boronic acid; And / or, the amino-substituted heteroaryl boronic acid is selected from any one or more of amino pyridyl boronic acid, amino bipyridyl boronic acid, amino thiophene boronic acid, amino furan boronic acid and amino pyrrole boronic acid.

7. The production method according to claim 4 or 5, characterized by, The second solvent is selected from any one or more of N,N-dimethylformamide, N-methyl pyrrolidone, N,N-dimethylacetamide and dimethyl sulfoxide; and / or the strong base catalyst is selected from any one or more of sodium hydroxide, potassium hydroxide and ammonium hydroxide; and / or the temperature of the nucleophilic substitution reaction is 80-120℃, and the time is 8-24h.

8. An improved electrically conductive paste composition, characterized by, The improved conductive paste composition comprises, in mass percentage: 30%-50% of conductive metal powder; 45% to 55% of the binder phase; 1% to 15% of the fourth solvent; 0.1% to 2% of the additive; The binder phase is the conductive adhesive of any one of claims 1 to 3 or is prepared by the method of any one of claims 4 to 7.

9. The improved conductive paste composition as claimed in claim 8, wherein, The additive includes 0.05 to 0.09% of the leveling agent, 1.3 to 1.5% of the thixotropic agent; and / or, the fourth solvent is selected from any one or more of ethyl acetate, acetone, methanol, ethanol, ethylene glycol ethyl ether, isopropyl alcohol, terpineol, diethylene glycol butyl ether.

10. An improved conductive paste, characterized by, The raw material of the improved conductive paste includes the improved conductive paste composition of claim 8 or 9, and the improved conductive paste is cured at a temperature lower than 100°C to form an electrode.

11. The improved conductive paste as claimed in claim 10, wherein, The improved conductive paste has an electrical conductivity of 1 x 10 4 ~ 1 x 10 7 S / m, and / or a coefficient of thermal expansion of 3.0 x 10 -6 / °C ~ 7.0 x 10 -6 / °C.

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