CN113480963B - Conductive adhesive, conductive adhesive tape and preparation method thereof - Google Patents

Conductive adhesive, conductive adhesive tape and preparation method thereof Download PDF

Info

Publication number
CN113480963B
CN113480963B CN202110563863.XA CN202110563863A CN113480963B CN 113480963 B CN113480963 B CN 113480963B CN 202110563863 A CN202110563863 A CN 202110563863A CN 113480963 B CN113480963 B CN 113480963B
Authority
CN
China
Prior art keywords
conductive adhesive
copper
formate
copper material
antioxidant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110563863.XA
Other languages
Chinese (zh)
Other versions
CN113480963A (en
Inventor
吴炳辉
杨剑豪
郑南峰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xiamen University
Tan Kah Kee Innovation Laboratory
Original Assignee
Xiamen University
Tan Kah Kee Innovation Laboratory
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xiamen University, Tan Kah Kee Innovation Laboratory filed Critical Xiamen University
Priority to CN202110563863.XA priority Critical patent/CN113480963B/en
Publication of CN113480963A publication Critical patent/CN113480963A/en
Application granted granted Critical
Publication of CN113480963B publication Critical patent/CN113480963B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
    • C09J175/04—Polyurethanes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J9/00—Adhesives characterised by their physical nature or the effects produced, e.g. glue sticks
    • C09J9/02—Electrically-conducting adhesives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • C08K2003/085—Copper
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/001—Conductive additives
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/314—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier the adhesive layer and/or the carrier being conductive
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2475/00—Presence of polyurethane

Abstract

The invention provides a conductive adhesive, a conductive adhesive tape and a preparation method thereof, wherein the conductive adhesive comprises 15-50 wt% of a copper material, 20-35 wt% of a water-based binder, 0-6 wt% of an auxiliary agent and the balance of a solvent; the copper material is a copper material at least decorated with formate on the surface, and the aqueous binder is polycarbonate modified aqueous polyurethane. The invention utilizes formate to modify the copper material, so that the long-range ordered and compact molecular oxidation resistant layer is formed on the surface of the copper, and O is inhibited2、Cl‑And OH‑The adsorption of the copper is realized, the intrinsic conductivity of Cu is not influenced, the waterborne polyurethane is further modified by the polycarbonate, the accumulation of hydrolysis products of the waterborne polyurethane is avoided, and the polycarbonate modified waterborne polyurethane and a copper material modified by formate act jointly to achieve an excellent antioxidant effect, so that the antioxidant copper conductive adhesive tape prepared by the invention has low volume resistivity and excellent stability.

Description

Conductive adhesive, conductive adhesive tape and preparation method thereof
Technical Field
The invention relates to the technical field of conductive adhesive materials, in particular to a conductive adhesive, a conductive adhesive tape and a preparation method thereof.
Background
The conductive adhesive tape is a special adhesive tape with high conductivity and capable of realizing bonding and packaging of electronic devices, and generally takes resin and conductive fillers as main components, and the conductive fillers are combined together through the bonding action of the resin to form a conductive path so as to realize conductive connection of bonded materials. At present, the conductive adhesive is widely applied to packaging and bonding of electronic elements and components such as Liquid Crystal Displays (LCDs), Light Emitting Diodes (LEDs), Integrated Circuit (IC) chips, dot matrix blocks, membrane switches, smart cards and the like, and the conductive adhesive has simple process and easy operation and can improve the production efficiency, so the conductive adhesive is an ideal choice for replacing lead-tin welding and realizing conductive connection.
The resin in the conductive adhesive tape provides the basic mechanical property of the conductive adhesive tape, determines the mechanical strength and the bonding stability of the conductive adhesive tape, and the epoxy resin is most widely used in the field of the conductive adhesive tape, but the epoxy resin has poor coating performance and strong internal stress, and a product is easy to break; polyurethane itself has good flexibility but poor heat resistance and weather resistance. In order to prevent electronic device failure and to cope with special and sudden situations, the conductive adhesive tape should have the ability to cope with extreme conditions, but at present, few resins meet the requirements. Therefore, the mechanical property and stability of the adhesive tape can be improved better by selecting a proper resin.
The conductive filler in the conductive tape can be gold, silver, copper, nickel powder, graphite and some conductive compounds. The silver powder has the advantages of good conductivity and strong oxidation resistance, but is expensive, and silver migration is easy to occur in a damp and hot environment, so that the resistance of the silver conductive adhesive is unstable; the nickel powder is low in price, but the resistance of the prepared conductive adhesive is improved by multiple times after a high-temperature lead-free welding process, so that certain hidden danger is caused to the reliability of a product; the copper powder has low price and good conductivity, but has poor oxidation resistance, and an oxidation film is easily formed on the surface of the copper powder after the copper powder is exposed in the air for a long time, so that the conductivity of the copper powder is greatly influenced. The use of the high-conductivity filler which is low in price and stable for a long time is a main factor for breaking through the development bottleneck of the conductive adhesive tape.
The trend of conductive adhesive tapes is to modify resin and conductive filler and simultaneously take into account various requirements of the resin and the conductive filler. CN109943252A discloses a silver-coated copper conductive adhesive and a preparation method thereof, wherein the conductive adhesive provided by the patent adopts organic silicon modified polyurethane as matrix resin, so that the impact capability, the vibration resistance and the temperature resistance of the conductive adhesive can be effectively improved; meanwhile, the silver-coated copper powder is adopted to replace low-copper powder or silver powder, so that the problem of high price of the silver powder is solved, and the defect that the copper powder is easy to oxidize is overcome; however, the surface of the copper powder is not completely coated by silver, the conductivity and the oxidation resistance of the copper powder are still lower than those of pure silver powder, copper ions generated after the coating process cannot be thoroughly cleaned, the copper ions can promote chemical reaction, the preparation time and the curing time are long, the shearing strength is insufficient, and the improvement is still needed. CN111205806A discloses a guideThe patent uses isooctyl acrylate and trimethylolpropane triacrylate to modify polyurethane and conductive filler to improve the adhesive force and conductivity of the conductive adhesive, and adds nano silver particles to further improve the conductivity, finally obtaining the Baige knife 5B with the bulk conductivity of 4.45 multiplied by 10-6Omega m conductive adhesive. But the silver-coated copper and the nano silver particles are used as the conductive filler, so that the manufacturing cost is greatly increased, and the acrylic resin has poor aging resistance and stability.
Therefore, in order to solve the above problems, there is a need for a conductive adhesive and a conductive adhesive tape thereof, which have excellent conductive properties, are inexpensive, are stable for a long period of time, and can cope with extreme conditions.
Disclosure of Invention
In order to solve the problems, the invention provides an antioxidant copper conductive adhesive tape, wherein a copper material is modified by formic acid radicals, so that a long-range ordered and compact molecular antioxidant layer is formed on the surface of copper, and O is inhibited2、Cl-And OH-The adsorption of the copper-based copper material is realized, the intrinsic conductivity of Cu is not influenced, the waterborne polyurethane is further modified by polycarbonate, the accumulation of hydrolysis products of the waterborne polyurethane is avoided, the polycarbonate-based copper material and the copper material modified by the formate act jointly, and the excellent antioxidant effect is achieved.
The invention provides a conductive adhesive, which is prepared from the following raw materials in percentage by mass: 15-50 wt% of copper material, 20-35 wt% of water-based binder, 0-6 wt% of assistant and the balance of solvent; the copper material is a copper material at least decorated with formate on the surface, and the aqueous binder is polycarbonate modified aqueous polyurethane.
Further, the copper material is of a hierarchical structure, preferably a dendritic structure.
Further, the copper material is copper powder or copper alloy powder, preferably copper powder.
Furthermore, mercaptan is modified on the surface of the copper material.
Further, the auxiliary agent is one or two of 0-2 wt% of silane coupling agent and 0-5 wt% of resin stabilizer.
Preferably, the silane coupling agent is KH560, and the resin stabilizer is carbodiimide and/or hindered phenol.
The invention provides a conductive adhesive tape, which comprises a substrate and conductive adhesive coated on one surface or two surfaces of the substrate, wherein the conductive adhesive is prepared from the following raw materials in percentage by mass: 15-50 wt% of copper material, 20-35 wt% of water-based binder, 0-6 wt% of assistant and the balance of solvent; the copper material is a copper material at least decorated with formate on the surface, and the aqueous binder is polycarbonate modified aqueous polyurethane.
The third aspect of the present invention provides a method for preparing a conductive adhesive, including:
s1: performing anti-oxidation treatment, namely putting the copper material into a solution containing a corrosion inhibitor, sealing and reacting for 0.01-100 h at the temperature of 20-300 ℃, and cleaning and drying to obtain an anti-oxidation copper material; the corrosion inhibitor at least contains one or two of formic acid and formate;
s2: preparing an antioxidant copper conductive adhesive, namely weighing 20-35 wt% of polycarbonate modified waterborne polyurethane, 0-6 wt% of an auxiliary agent, 15-50 wt% of an antioxidant copper material and the balance of a solvent by mass percent, grinding, stirring at a rotating speed of 1000-3000 rpm for 3-10 min, and carrying out bubble extraction to obtain the antioxidant copper conductive adhesive; further, the solvent is at least one selected from ethylene glycol butyl ether, ethanol, n-butanol, diethylene glycol, propylene glycol, deionized water, glycerol, acetone, isopropanol, triethanolamine and aminomethyl propanol;
further, the copper material in the step S1 is a dendritic copper material; the preparation method of the dendritic copper material comprises the following steps: copper is used as an anode, titanium is used as a cathode and is placed in electrolyte for electrolysis, and dendritic copper materials are collected on the cathode.
Further, the formate is selected from at least one of lithium formate, sodium formate, magnesium formate, aluminum trimethyl carbonate, potassium formate, ammonium formate, calcium formate, zinc formate, iron formate, copper formate, barium formate, beryllium formate, nickel formate, cobalt formate and manganese formate.
Further, the corrosion inhibitor further comprises a mercaptan.
Further, the thiol is at least one selected from the group consisting of methyl thiol, ethyl thiol, ethylene glycol thiol, dodecyl thiol, hexadecyl thiol, 1-propyl thiol, 1, 3-propanedithiol, mercaptoethanol, mercaptopyridine and derivatives thereof, cysteine, glutathione, and mercaptoethylamine.
Further, the 0-6 wt% of auxiliary agent is one or two of 0-2 wt% of silane coupling agent and 0-5 wt% of resin stabilizer; preferably, the silane coupling agent is KH560, and the resin stabilizer is carbodiimide and/or hindered phenol.
Further, the preparation method of the polycarbonate modified waterborne polyurethane comprises the following steps:
(A) putting hexamethylene diisocyanate, polycarbonate dihydric alcohol, polytetrahydrofuran ether glycol, 1, 4-butanediol and bis (hydroxymethyl) propionic acid into a vacuum condition for dehydration;
(B) adding the polycarbonate diol and the polytetrahydrofuran ether glycol subjected to vacuum dehydration in the step (A) into a flask, and heating to remove moisture;
(C) taking dibutyltin dilaurate in N2Adding the hexamethylene diisocyanate subjected to vacuum dehydration in the step (A) in the atmosphere, and then adding dimethylolpropionic acid to obtain a prepolymer;
(D) adding acetone and the 1, 4-butanediol dehydrated in the step (A) into the prepolymer obtained in the step (C), and adding triethylamine to obtain a mixed solution;
(E) and (D) distilling the mixed solution obtained in the step (D) under reduced pressure, and adding a solvent to prepare the polycarbonate modified waterborne polyurethane.
The fourth aspect of the present invention provides a method for producing a conductive adhesive tape, comprising:
s1: performing anti-oxidation treatment, namely putting the copper material into a solution containing a corrosion inhibitor, sealing and reacting for 0.01-100 h at the temperature of 20-300 ℃, and cleaning and drying to obtain an anti-oxidation copper material; the corrosion inhibitor at least contains one or two of formic acid and formate;
s2: preparing an antioxidant copper conductive adhesive, namely weighing 20-35 wt% of polycarbonate modified waterborne polyurethane, 0-6 wt% of an auxiliary agent, 15-50 wt% of an antioxidant copper material and the balance of a solvent by mass percent, grinding, stirring at a rotating speed of 1000-3000 rpm for 3-10 min, and carrying out bubble extraction to obtain the antioxidant copper conductive adhesive;
s3: and preparing the antioxidant copper conductive adhesive tape, namely coating and printing the antioxidant copper conductive adhesive, and preheating and curing at 60-100 ℃ for 5-20 min to obtain the antioxidant copper conductive adhesive tape.
Compared with the prior art, the oxidation-resistant copper conductive adhesive tape provided by the invention has the advantages that the copper material is hydrothermally treated by using the formate solution, so that the Cu surface is reconstructed into a (110) crystal face, and a copper formate dimer binuclear [ Cu (mu-HCOO) (OH) is further formed2]2And O2-Long-range ordered and compact molecular oxidation resisting layer comprising hydroxyl radical not only inhibits O2C1-and OH-are adsorbed, and the intrinsic conductivity of Cu is not influenced. However, because polyurethane is easily hydrolyzed in the long-term use process, products such as carboxylic acid and alcohol, and alcohol substances and formate undergo esterification reaction, so that formate is desorbed, an oxidation resistant layer is damaged, and the conductivity of a system is affected, the waterborne polyurethane is further modified by Polycarbonate (PC), and the polycarbonate hydrolysate is only CO2The accumulation of the hydrolysis product of the waterborne polyurethane is avoided, and the copper material modified by the formate acts jointly to achieve an excellent antioxidant effect. Meanwhile, as the polycarbonate contains high-polarity carbonate group-O- (C ═ O) -O-and has high glass transition temperature, the polycarbonate can be used as a continuous phase carrier of the composite conductive material, copper materials can be better dispersed and fixed in polyurethane resin, and the conductivity of the system is further improved, so that the prepared antioxidant copper conductive adhesive tape has lower volume resistivity and excellent stability.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.
FIG. 1 is an SEM image of dendritic copper powder prepared according to the invention;
FIG. 2 is an SEM image of the antioxidant dendritic copper powder conductive adhesive prepared by the invention;
FIG. 3 is an SEM image of the conductive paste prepared in comparative example 4;
FIG. 4 is an SEM image of a conductive paste prepared in comparative example 5;
FIG. 5 is an SEM image of the spherical copper powder conductive adhesive prepared in comparative example 10;
FIG. 6 is an SEM image of the flake copper powder conductive paste prepared in comparative example 11;
FIG. 7 is a flow chart of the preparation of the antioxidant dendritic copper powder of the present invention;
FIG. 8 is a schematic diagram of the process for preparing the conductive tape and its use of the present invention;
FIG. 9 is a diagram of the conductive tape and its application.
Detailed Description
Other advantages and features of the present invention will become readily apparent to those skilled in this art from the following detailed description of the preferred embodiment when taken in conjunction with the drawings wherein like reference numerals designate like parts in the several views.
It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for understanding and reading the present disclosure, and are not used for limiting the conditions of the present disclosure, which will not be technically significant, and any structural modifications, ratio changes or size adjustments should fall within the scope of the present disclosure without affecting the function and the achievable purpose of the present disclosure. In addition, the terms "upper", "inner", "outer", "bottom", "one" and "middle" used in the present specification are for convenience of description and are not intended to limit the scope of the present invention, and changes or modifications in the relative relationship may be made without substantial changes in the technical content.
The invention provides a conductive adhesive, which is prepared from the following raw materials in percentage by mass: 15-50 wt% of copper material, 20-35 wt% of water-based binder, 0-6 wt% of assistant and the balance of solvent.
Furthermore, the copper material in the conductive adhesive is preferably 25-40 wt%, the polycarbonate modified waterborne polyurethane is 25-35 wt%, the auxiliary agent is 2-4 wt%, and the balance is a solvent, as shown in fig. 2, an SEM image of the antioxidant dendritic copper powder conductive adhesive prepared by the invention is shown.
According to an embodiment of the present invention, the copper material is a copper material with a surface modified with at least formate, for example, the copper material may be a copper material modified with formate, or a copper material modified with formate and thiol, including but not limited to.
According to an embodiment of the present invention, the aqueous binder is a polycarbonate modified aqueous polyurethane.
According to the embodiment of the invention, the auxiliary agent is one or more of 0-2 wt% of silane coupling agent, 0-3 wt% of carbodiimide and 0-2 wt% of hindered phenol;
wherein the silane coupling agent is selected from KH560, including but not limited thereto; the resin stabilizer is selected from carbodiimide and/or hindered phenol, including but not limited to.
According to the embodiment of the invention, the copper material is of a hierarchical structure, preferably a dendritic structure, and as shown in fig. 1, the SEM image of the dendritic copper powder prepared by the invention is shown.
According to an embodiment of the invention, the copper material is copper powder.
The invention further provides a conductive adhesive tape, which comprises a substrate and conductive adhesive coated on one surface or two surfaces of the substrate, wherein the conductive adhesive is prepared from the following raw materials in percentage by mass: 15-50 wt% of copper material, 20-35 wt% of water-based binder, 0-6 wt% of assistant and the balance of solvent. .
The invention also provides a preparation method of the conductive adhesive, which comprises the following steps:
(1) the anti-oxidation treatment method comprises the following steps: placing copper powder in a polar solvent containing a corrosion inhibitor, carrying out sealing reaction for 0.01-100 h in a pressure-resistant container at the temperature of 20-300 ℃, cleaning with water or ethanol, and drying to obtain antioxidant copper powder, wherein at least one layer of formate is adsorbed on the surface of the dendritic copper powder;
according to embodiments of the present invention, the corrosion inhibitor may be selected from the group consisting of formic acid, formate salts, and the like; the formate can be at least one selected from lithium formate, sodium formate, magnesium formate, aluminum trimethyl carbonate, potassium formate, ammonium formate, calcium formate, zinc formate, iron formate, copper formate, barium formate, beryllium formate, nickel formate, cobalt formate, manganese formate and the like; the polar solvent can be at least one selected from water, amide solvent, alcohol solvent, ester solvent, ether solvent, etc.; the amide solvent can be at least one selected from formamide, dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, dimethylpropionamide and the like; the alcoholic solvent can be at least one selected from monohydric alcohol, dihydric alcohol, polyhydric alcohol, etc.;
according to the embodiment of the invention, the copper powder is in a dendritic structure, and the specific preparation method comprises the following steps: placing a copper anode plate and a titanium cathode plate in electrolyte prepared from 180g/L of sulfuric acid, 160g/L of copper sulfate pentahydrate and 0.5g/L of hydrochloric acid, wherein the plate distance is 3-5 cm, the temperature of the electrolyte is 30-50 ℃, and the current density is 50-500 mA/cm2Electrolyzing for 30-180 min under the condition, collecting the dendritic copper powder obtained on the negative plate by matching ultrasonic with a scraper, and collecting the dendritic copper powder on the negative plate once every 3-5 min;
according to the embodiment of the invention, the anti-oxidation copper powder further comprises thiol modification, and the specific preparation method comprises the following steps: adding a formate solution with the concentration of 1-15 mol/L and a solvent into a first container, uniformly stirring to obtain a mixed solution, wherein the solvent comprises an alcohol solution and at least one of oleylamine, n-octylamine, dodecylamine, n-tridecylamine, dodecyl dimethyl tertiary amine or octadecyl amine, placing the obtained dendritic copper powder into the first container containing the mixed solution, reacting at the temperature of 80-180 ℃ for 0.5-24 h, pouring out a supernatant, adding a 1.0 x 10 concentration-4～1.0×10-1And (3) reacting the mercaptan in a mol/L manner for 0.5-30 min, and then carrying out liquid-solid separation, washing and drying treatment to obtain the antioxidant copper powder jointly modified by formate and the mercaptan. FIG. 7 is a flow chart of the preparation of the antioxidant dendritic copper powder of the present invention.
According to an embodiment of the invention, the thiol is selected from at least one of methyl thiol, ethyl thiol, ethylene glycol thiol, dodecyl thiol, hexadecyl thiol, 1-propyl thiol, 1, 3-propanedithiol, mercaptopyridine and derivatives thereof, mercaptoethanol, cysteine, glutathione, mercaptoethylamine.
(2) Preparing the antioxidant copper conductive adhesive: weighing 20-35 wt% of water-based binder, 0-6 wt% of assistant, 15-50 wt% of antioxidant copper powder and the balance of solvent, grinding by three rollers, stirring for 3-10 min at the rotating speed of 1000-3000 rpm by a homogenizer, defoaming under a vacuum condition, and pumping bubbles to obtain the antioxidant copper conductive adhesive;
further, preferably, 25-35 wt% of polycarbonate modified waterborne polyurethane, 2-4 wt% of an auxiliary agent, 25-40 wt% of the antioxidant copper powder and the balance of a solvent are weighed.
According to an embodiment of the present invention, the aqueous binder is a polycarbonate-modified aqueous polyurethane.
According to an embodiment of the present invention, a method for preparing a polycarbonate-modified aqueous polyurethane comprises:
(A) putting hexamethylene diisocyanate, polycarbonate dihydric alcohol, polytetrahydrofuran ether glycol, 1, 4-butanediol and bis (hydroxymethyl) propionic acid into a vacuum condition for dehydration, and drying at the temperature of 80 ℃ for 2 hours;
(B) adding the polycarbonate diol after vacuum dehydration and the polytetrahydrofuran ether glycol after vacuum dehydration in a mass ratio of 1: 4 into a four-neck flask with a stirrer and a condenser, heating to 105 ℃, preserving heat for 1h, and removing water;
(C) cooling to 70 deg.C, introducing N2Adding dibutyltin dilaurate and vacuum dehydrated hexamethylene diisocyanate, adding dimethylolpropionic acid for continuous reaction to obtain a prepolymer, and testing the NCO content to a theoretical value; wherein the dimethylolpropionic acid accounts for 6-8% of the mass of the prepolymer;
(D) adding acetone and vacuum dehydrated 1, 4-butanediol into the prepolymer, reacting for 1h, cooling to 40 ℃, adding triethylamine for neutralization, adding a certain amount of water, and stirring for 10min to obtain a mixed solution; wherein 1, 4-butanediol accounts for 2-3% of the prepolymer by mass;
(E) and distilling the mixed solution under reduced pressure, distilling out acetone under 0.01MPa, and adding water to adjust the viscosity and the solid content to obtain the polycarbonate modified waterborne polyurethane.
According to the examples of the present invention, the polycarbonate-modified aqueous polyurethane was prepared so as to have a solid content of 35% and a viscosity of 500 mPas.
According to the embodiment of the invention, the 0-6 wt% of the auxiliary agent is one or two of 0-2 wt% of silane coupling agent and 0-5 wt% of resin stabilizer, wherein the resin stabilizer is selected from 0-3 wt% of carbodiimide and/or 0-2 wt% of hindered phenol.
According to an embodiment of the present invention, the solvent is selected from at least one of ethylene glycol butyl ether, ethanol, n-butanol, diethylene glycol butyl alcohol, propylene glycol, deionized water, glycerol, acetone, isopropanol, triethanolamine, aminomethyl propanol.
The invention further provides a preparation method of the conductive adhesive tape, which comprises the following steps:
(1) the anti-oxidation treatment method comprises the following steps: placing copper powder in a polar solvent containing a corrosion inhibitor, carrying out sealing reaction for 0.01-100 h in a pressure-resistant container at the temperature of 20-300 ℃, cleaning with water or ethanol, and drying to obtain antioxidant copper powder, wherein at least one layer of formate is adsorbed on the surface of the dendritic copper powder;
(2) preparing the antioxidant copper conductive adhesive: weighing 20-35 wt% of water-based binder, 0-6 wt% of assistant, 15-50 wt% of antioxidant copper powder and the balance of solvent, grinding by three rollers, stirring for 3-10 min at the rotating speed of 1000-3000 rpm by a homogenizer, defoaming under a vacuum condition, and pumping bubbles to obtain the antioxidant copper conductive adhesive;
(3) preparing an oxidation-resistant copper conductive adhesive tape: and (3) coating and printing the obtained antioxidant copper conductive adhesive tape, and preheating and curing the antioxidant copper conductive adhesive tape at the temperature of 60-100 ℃ for 5-20 min to obtain the antioxidant copper conductive adhesive tape.
According to the embodiment of the invention, when the anti-oxidation conductive adhesive tape is used, the conductive adhesive tape is torn off from the PET release film and is placed on the PI film for hot pressing; according to the embodiment of the invention, the hot pressing condition is 3-5 MPa, the hot pressing temperature is 120-140 ℃, and the hot pressing time is 60-70 min.
FIG. 8 is a schematic diagram of the process for preparing the conductive tape and its application. FIG. 9 is a diagram of a conductive tape and an application of the conductive tape, wherein FIG. 9(a) is a diagram of a conductive tape and a PET substrate; FIG. 9(b) is a conductive tape back pressure steel plate; FIG. 9(c) is a view showing the conductive tape connecting two steel plates; FIG. 9(d) is a view showing the conductive tape connecting the steel plate and the device; fig. 9(e) shows a one-dimensional coin.
The detailed manufacturing process and conditions of the preparation method provided by the present invention are described below by examples.
Example 1
According to the method provided by the present invention,
(1) preparing dendritic copper powder: placing an anode plate (a phosphorus copper system in the example) and a cathode plate (a titanium plate system in the example) in an electrolyte for electrolysis, and collecting dendritic copper powder obtained on the cathode plate by matching ultrasonic with a scraper, wherein the electrolyte is 180g/L sulfuric acid, 160g/L copper sulfate pentahydrate and 0.5g/L hydrochloric acid, the electrolysis temperature is 30-50 ℃, the plate interval is 5cm, and the current density is 200mA/cm2Collected every 3 min;
(2) and (3) antioxidant treatment: putting the obtained dendritic copper powder into a solution with 16g/L of sodium formate as a corrosion inhibitor and 0.940g/mL of N, N-dimethylformamide as a polar solvent, sealing and reacting in a pressure-resistant container at the temperature of 150 ℃ for 18h, cleaning with ethanol, drying for later use, and sieving to obtain the antioxidant dendritic copper powder modified by formate with the particle size of about 3 mu m;
(3) weighing 30 wt% of the antioxidant dendritic copper powder, 33 wt% of polycarbonate modified waterborne polyurethane, 35.8 wt% of solvent, 0.2 wt% of silane coupling agent, 0.6 wt% of carbodiimide and 0.4 wt% of hindered phenol, carrying out three-roll grinding treatment, and uniformly mixing and foaming at 1500rpm for 5min by a homogenizer to obtain antioxidant copper conductive adhesive;
(4) coating the antioxidant copper conductive adhesive on a PET release film substrate by using a slit coating machine, and placing the PET release film substrate in an oven at 100 ℃ for 5-10 min to solidify the surface to obtain an antioxidant copper conductive adhesive tape;
(5) in the process of using the antioxidant copper conductive adhesive tape, the conductive adhesive tape is torn off from a PET release film and placed on a PI film for hot pressing, wherein the hot pressing condition is 3-5 MPa, the temperature is 120-140 ℃, and the hot pressing time is 60-70 min.
The conductive tape prepared in example 1 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 2.02X 10-6Ω · m, shear strength 12.73MPa, peel force (PI) 9.5N/cm, adhesion (PI) 5B.
And (3) stability testing: after 1000h, the test of stability (test conditions 25 ℃, 50% RH, 1atm) was carried out, and the volume resistivity was 2.11X 10-6Ω · m, the volume resistivity of which does not significantly decrease.
And (3) accelerated aging test: performing 1000h accelerated aging test in a constant temperature and humidity chamber (test conditions of 85 deg.C, 85% RH, 1atm) with volume resistivity of 1.01 × 10-5Omega.m, the change rate is 400 percent, and still meets the use requirement.
Alkali resistance test: soaking in 0.1M NaOH for 10h for alkali resistance test, the volume resistivity is 2.19 multiplied by 10-6Ω · m, the volume resistivity thereof does not significantly decrease.
And (3) salt spray testing: no significant oxidation occurred after 24h salt spray testing.
Example 2
According to the method provided by the present invention,
the preparation steps and materials of this example 2 are the same as those of example 1, except that 50 wt% of the antioxidant dendritic copper powder, 23 wt% of the polycarbonate modified waterborne polyurethane, 25.8 wt% of the solvent, 0.2 wt% of the silane coupling agent, 0.6 wt% of the carbodiimide and 0.4 wt% of the hindered phenol are weighed in the step (3), and the antioxidant copper conductive adhesive is obtained by three-roll grinding, uniformly mixing and foaming at 1500rpm for 5min by a homogenizer, and the selection of the rest preparation steps and materials is the same as that of example 1.
The conductive tape prepared in example 2 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 1.67X 10-6Omega. m, shear strength of 13.85MPa, peel force (PI) of 10.1N/cm, adhesion (PI) of 5B.
And (3) testing the stability: stability test after 1000h (test strip)25 ℃ 50% RH, 1atm), volume resistivity of 1.76X 10-6Ω · m, the volume resistivity thereof does not significantly decrease.
And (3) accelerated aging test: performing 1000h accelerated aging test in a constant temperature and humidity chamber (test conditions of 85 deg.C, 85% RH, 1atm) with volume resistivity of 8.52 × 10-6Omega.m, the change rate is 410 percent, and still meets the use requirement.
Alkali resistance test: soaking in 0.1M NaOH for 10h for alkali resistance test, the volume resistivity is 1.82 multiplied by 10-6Ω · m, the volume resistivity thereof does not significantly decrease.
And (3) salt spray testing: no significant oxidation occurred after 24h salt spray testing.
Example 3
According to the method provided by the present invention,
in this example 3, the preparation steps and material selection are the same as those in example 1, except that the antioxidant treatment in the step (2) is carried out to obtain antioxidant copper powder co-modified by formate and mercaptan, and the specific antioxidant treatment is as follows: 30mL of propylene glycol, 1mL of n-octylamine and 1mL of magnesium formate solution are added to a container and stirred uniformly. Then the washed copper powder is placed in a container containing the mixed solution and heated and stirred for 3 hours at the temperature of 100 ℃. After natural cooling, the supernatant was decanted off and 20mL of 1.0X 10- 3The mol/L cysteine was stirred for 10 min. And carrying out suction filtration and drying to obtain the antioxidant dendritic copper powder jointly modified by formate and mercaptan, wherein the rest preparation steps and the selection of materials are the same as those in example 1.
The conductive tape prepared in example 3 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 1.46X 10-6Omega. m, a shear strength of 16.226MPa, a peel force (PI) of 10.5N/cm and an adhesion (PI) of 5B.
And (3) stability testing: after 1000h, the test of stability (test conditions of 25 ℃, 50% RH, 1atm) was carried out, and the volume resistivity was 1.52X 10-6Ω · m, the volume resistivity thereof does not significantly decrease.
Accelerated aging test: the 1000h accelerated aging test is carried out in a constant temperature and humidity box (the test conditions are 85 ℃, 85 percent RH, 1atm), volume resistivity of 7.92 × 10-6Omega m, the change rate is 442%, and the use requirement is still met.
Alkali resistance test: the volume resistivity is 1.62 multiplied by 10 in the alkali resistance test of soaking 0.1M NaOH for 10h-6Ω · m, the volume resistivity thereof does not significantly decrease.
And (3) salt spray testing: no significant oxidation occurred after 24h salt spray testing.
Example 4
According to the method provided by the present invention,
this example 4 is similar to example 3 in preparation steps and material selection, except that 50 wt% of the antioxidant dendritic copper powder, 23 wt% of the polycarbonate modified waterborne polyurethane, 25.8 wt% of the solvent, 0.2 wt% of the silane coupling agent, 0.6 wt% of the carbodiimide, and 0.4 wt% of the hindered phenol are weighed in step (3), and are subjected to three-roll grinding treatment, and are uniformly mixed and bubbled at 1500rpm for 5min by a homogenizer to obtain the antioxidant copper conductive adhesive, and the rest of the preparation steps and material selection are similar to example 3.
The dendritic copper powder prepared in this example is shown in fig. 1, the antioxidant dendritic copper powder conductive adhesive prepared in this example is shown in fig. 2, and the prepared conductive adhesive tape is subjected to performance test, wherein the conductive adhesive tape has a thickness of 75 micrometers and a volume resistivity of 1.31 × 10-6Omega. m, a shear strength of 13.550MPa, a peel force (PI) of 11.8N/cm and an adhesion (PI) of 5B.
And (3) stability testing: after 1000h, the test of stability (test conditions of 25 ℃, 50% RH, 1atm) was carried out, and the volume resistivity was 1.36X 10-6Ω · m, the volume resistivity thereof does not significantly decrease.
Accelerated aging test: performing 1000h accelerated aging test in a constant temperature and humidity chamber (test conditions of 85 deg.C, 85% RH, 1atm) with volume resistivity of 5.88 × 10-6Omega m, the change rate is 349%, and the use requirement is still met.
Alkali resistance test: soaking in 0.1M NaOH for 10h for alkali resistance test, the volume resistivity is 1.40 multiplied by 10-6Ω · m, the volume resistivity thereof does not significantly decrease.
And (3) salt spray testing: no significant oxidation occurred after 24h salt spray testing.
TABLE 1
Figure BDA0003079933300000101
Figure BDA0003079933300000111
Table 1 shows parameters of a performance test, a stability test, an anti-aging performance test, and an alkali resistance test of the conductive adhesive tape prepared in examples 1 to 4, and it can be seen that the conductive adhesive tape prepared by modifying copper powder and polyurethane resin according to the method provided by the present invention has good stability and alkali resistance, has no significant decrease in volume resistivity, and can well cope with a special environment.
Comparative example 1
(1) Preparing dendritic copper powder: placing an anode plate (a phosphorus copper system in the example) and a cathode plate (a titanium plate system in the example) in an electrolyte for electrolysis, and collecting dendritic copper powder obtained on the cathode plate by matching ultrasonic with a scraper, wherein the electrolyte is 180g/L sulfuric acid, 160g/L copper sulfate pentahydrate and 0.5g/L hydrochloric acid, the electrolysis temperature is 30-50 ℃, the plate interval is 5cm, and the current density is 200mA/cm2Collected every 3 min;
(2) weighing 50 wt% of the dendritic copper powder, 23 wt% of polycarbonate modified waterborne polyurethane resin, 25.8 wt% of solvent, 0.2 wt% of silane coupling agent, 0.6 wt% of carbodiimide and 0.4 wt% of hindered phenol, carrying out three-roll grinding treatment, and uniformly mixing and foaming at 1500rpm for 5min by a homogenizer to obtain dendritic conductive adhesive;
(3) coating the dendritic conductive adhesive on a PET release film substrate by using a slit coating machine, and placing the PET release film substrate in an oven at 100 ℃ for 5-10 min to solidify the surface to obtain a dendritic conductive adhesive tape;
(4) in the process of using the dendritic conductive adhesive tape, the conductive adhesive tape is torn off from a PET release film and placed on a PI film for hot pressing, wherein the hot pressing condition is 3-5 MPa, the temperature is 120-140 ℃, and the hot pressing time is 60-70 min.
The conductive tape prepared in comparative example 1 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 1.52X 10-2Omega. m, a shear strength of 9.62MPa, a peel force (PI) of 7.3N/cm and an adhesion (PI) of 5B.
And (3) stability testing: after 500 hours, the test was carried out for stability (test conditions of 25 ℃ C., 50% RH, 1atm) and the volume resistivity was 13.66. omega. m.
Accelerated aging test: and (4) performing 1000h accelerated aging test (the test conditions are 85 ℃, 85% RH and 1atm) in a constant temperature and humidity chamber to fail.
The dendritic copper powder is adopted in the comparative example, oxidation resistance treatment is not carried out on the dendritic copper powder, the oxidation resistance is poor, and an oxidation film is easily formed on the surface of the dendritic copper powder after the dendritic copper powder is exposed in the air for a long time, so that the conductivity is reduced.
Alkali resistance test: and when the conductive adhesive tape is soaked in 0.1M NaOH for 10h in an alkali resistance test, the conductive adhesive tape fails.
Comparative example 2
Comparative example 2 the preparation steps and materials were selected as in example 2, except that in comparative example 2, the antioxidant treatment in step (2) yielded antioxidant copper powder modified with thiol reagent alone, and the specific thiol reagent antioxidant treatment was: cleaning the collected dendritic copper powder with clear water, performing anti-oxidation treatment by using a thiol reagent, soaking the copper powder in the thiol reagent, performing ultrasonic treatment at the ultrasonic treatment frequency of 50kHz for 10min, and controlling the temperature at 25 ℃. After cooling, the mixture was placed in a centrifuge tube at 10000rpm and repeated several times. And pouring out the centrifugate, carrying out vacuum drying on the particles in the centrifuge tube by using a mobile phone, and sieving the particles by using a sieve to obtain the dendritic copper powder with the particle size of about 3 mu m, wherein the rest preparation steps and materials are the same as those in the example 2.
The conductive tape prepared in comparative example 2 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 6.90X 10-6Omega.m, the shear strength is 12.879MPa, the peeling force (PI) is 8.8N/cm, the adhesive force (PI) is 5B, the resistance continuously rises when the conductive adhesive tape is placed at room temperature, and the conductive adhesive tape fails in a double 85 accelerated aging test.
Comparative example 3
The preparation steps and materials of the comparative example 3 are the same as those of the comparative example 2, except that the antioxidant copper powder modified by the imidazole reagent is obtained by the antioxidant treatment of the comparative example 3 in the step (2), namely, the collected dendritic copper powder is washed by clear water and then is subjected to antioxidant treatment by using the imidazole reagent, 2-phenylimidazole is adopted in the comparative example 3, and the dendritic copper powder and the imidazole compound are prepared according to the mass ratio of 10: 3, 1 percent of dendritic copper powder in the dendritic copper powder dispersion liquid by mass percent, isopropanol as a solvent, ultrasonic treatment frequency of 50kHz, treatment time of 10min and control temperature of 25 ℃. After cooling, the mixture was placed in a centrifuge tube at 10000rpm and repeated several times. And pouring out the centrifugate, carrying out vacuum drying on the particles in the centrifuge tube by using a mobile phone, sieving the particles by using a screen to obtain the dendritic copper powder with the particle size of about 3 mu m, and selecting the rest preparation steps and materials as in the comparative example 2.
The conductive tape prepared in comparative example 3 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 5.70X 10-5Omega.m, the shear strength is 5.564MPa, the peeling force (PI) is 6.6N/cm, the adhesive force (PI) is 5B, the resistance continuously rises when the conductive adhesive tape is placed at room temperature, and the conductive adhesive tape fails in a double 85 accelerated aging test.
Alkali resistance test: the volume resistivity is 3.04 multiplied by 10 in the alkali resistance test of 0.1MNaOH 10h-2Ω·m。
Comparative example 4
The preparation steps and materials of the comparative example 4 are the same as those of the example 2, except that 50 wt% of the antioxidant dendritic copper powder, 11.5 wt% of epoxy resin, 11.5 wt% of polyamide curing agent, 25.8 wt% of solvent, 0.2 wt% of silane coupling agent, 0.6 wt% of carbodiimide and 0.4 wt% of hindered phenol are weighed in the step (3) of the comparative example 4, and are subjected to three-roll grinding treatment, mixed uniformly at 1500rpm for 5min by a homogenizer and subjected to bubble extraction to obtain the dendritic copper conductive adhesive, and the other preparation steps and materials are the same as those of the example 2. The conductive paste prepared in this comparative example 4 is shown in fig. 3.
The prepared conductive adhesive tape is further subjected to performance test, and the thickness of the conductive adhesive tape is 75 micrometers, and the volume resistivity of the conductive adhesive tape is 7.5 multiplied by 10-5Omega. m, shear strength 21.787MPa, peelThe peel force (PI) was 13.3N/cm and the adhesion force (PI) was 5B.
And (3) stability testing: after 1000h, the test of stability (test conditions 25 ℃, 50% RH, 1atm) was carried out, and the volume resistivity was 1.3X 10-4Ω·m。
Accelerated aging test: the accelerated aging test is carried out for 1000h in a constant temperature and humidity box (the test conditions are 85 ℃, 85% RH and 1atm), the volume resistivity is 1.55 omega-m, and the resistivity changes violently.
Alkali resistance test: the volume resistivity is 3.11 multiplied by 10 in the alkali resistance test of soaking for 0.1M NaOH 10h-3Ω·m。
Comparative example 5
The preparation steps and materials of the comparative example 5 are the same as those of the example 2, except that 50 wt% of the antioxidant dendritic copper powder, 23 wt% of the phenolic resin, 25.8 wt% of the solvent, 0.2 wt% of the silane coupling agent, 0.6 wt% of the carbodiimide and 0.4 wt% of the hindered phenol are weighed in the step (3) of the comparative example 5, and are subjected to three-roll grinding treatment, uniformly mixed and bubbled at 1500rpm for 5min through a homogenizer to obtain the dendritic copper conductive adhesive, and the rest of the preparation steps and materials are the same as those of the example 2. The conductive paste prepared in this comparative example 5 is shown in fig. 4.
The prepared conductive adhesive tape is subjected to performance test, the thickness of the conductive adhesive tape is 75 micrometers, and the volume resistivity of the conductive adhesive tape is 8.5 multiplied by 10-6Omega. m, the cured conductive tape was too brittle to be tested for shear strength and peel strength.
Comparative example 6
The preparation steps and materials of the comparative example 6 are the same as those of the example 2, except that 50 wt% of the antioxidant dendritic copper powder, 23 wt% of the oil-based polyurethane, 25.8 wt% of the solvent, 0.2 wt% of the silane coupling agent, 0.6 wt% of the carbodiimide and 0.4 wt% of the hindered phenol are weighed in the step (3) of the comparative example 6, and are subjected to three-roll grinding treatment, uniformly mixed and bubbled at 1500rpm for 5min through a homogenizer to obtain the dendritic copper conductive adhesive, and the rest of the preparation steps and materials are the same as those of the example 2.
The conductive tape prepared in comparative example 6 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 2.54X 10-4Omega. m, shear strength 15.670MPaThe peel force (PI) was 9.2N/cm, and the adhesion force (PI) was 5B.
And (3) stability testing: after 1000h, the test of stability (test conditions of 25 ℃, 50% RH, 1atm) was carried out, and the volume resistivity was 8.85X 10-4Ω·m。
Accelerated aging test: the accelerated aging test is carried out for 1000h in a constant temperature and humidity box (the test conditions are 85 ℃, 85% RH and 1atm), the volume resistivity is 1.55 ohm-m, and the resistivity changes violently.
Alkali resistance test: the volume resistivity is 9.04 multiplied by 10 in the alkali resistance test of soaking for 0.1MNaOH 10h-3Ω·m。
Comparative example 7
The preparation steps and materials of the comparative example 7 are the same as those of the example 2, except that 50 wt% of the antioxidant dendritic copper powder, 23 wt% of the aqueous polyurethane, 25.8 wt% of the solvent, 0.2 wt% of the silane coupling agent, 0.6 wt% of the carbodiimide and 0.4 wt% of the hindered phenol are weighed in the step (3) of the comparative example 7, the mixture is subjected to three-roll grinding treatment, uniformly mixed and bubbled at 1500rpm for 5min through a homogenizer to obtain the dendritic copper conductive adhesive, and the rest of the preparation steps and materials are the same as those of the example 2.
The conductive tape prepared in comparative example 7 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 5.51X 10-5Omega. m, a shear strength of 12.331MPa, a peel force (PI) of 9.4N/cm and an adhesion (PI) of 5B.
And (3) stability testing: after 1000h, the test of stability (test conditions of 25 ℃, 50% RH, 1atm) was carried out, and the volume resistivity was 9.30X 10-5Ω·m。
Accelerated aging test: performing 1000h accelerated aging test in a constant temperature and humidity chamber (test conditions of 85 deg.C, 85% RH, 1atm) with volume resistivity of 2.68 × 10-3Ω · m, rate of change 4764%. The aqueous polyurethane is adopted in the comparative example, and the conductivity is reduced because the aqueous polyurethane is easy to hydrolyze in the long-term use process, and esterification reaction is carried out on products such as carboxylic acid and alcohol, and alcohol substances and formic acid, so that formic acid radicals are desorbed, and an oxidation resistant layer is damaged.
Alkali resistance test: soaking for 0.1M NaOH 10h for resisting alkaliIn the sexual test, the volume resistivity is 2.03X 10-3Ω·m。
Comparative example 8
The preparation steps and materials of the comparative example 8 are the same as those of the example 2, except that 50 wt% of the antioxidant dendritic copper powder, 23 wt% of the aromatic waterborne polyurethane, 25.8 wt% of the solvent, 0.2 wt% of the silane coupling agent, 0.6 wt% of the carbodiimide and 0.4 wt% of the hindered phenol are weighed in the step (3) of the comparative example 8, the mixture is subjected to three-roll grinding treatment, is uniformly mixed and foamed at 1500rpm for 5min through a homogenizer to obtain the dendritic copper conductive adhesive, and the other preparation steps and materials are the same as those of the example 2.
The conductive tape prepared in comparative example 7 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 8.97X 10-5Omega. m, a shear strength of 14.889MPa, a peel force (PI) of 9.8N/cm and an adhesion (PI) of 5B.
And (3) stability testing: after 1000h, the test was carried out for stability (test conditions 25 ℃, 50% RH, 1atm) and the volume resistivity was 1.83X 10-4Ω·m。
Accelerated aging test: the aging test is carried out for 1000h in a constant temperature and humidity chamber (the test conditions are 85 ℃, 85 percent RH and 1atm), the volume resistivity is 1.47 multiplied by 10-2Ω · m, change rate 16288%.
Alkali resistance test: the volume resistivity is 9.17 multiplied by 10 in the alkali resistance test of soaking for 0.1MNaOH 10h-3Ω·m。
Comparative example 9
The preparation steps and materials of the comparative example 9 are the same as those of the example 2, except that 50 wt% of the antioxidant dendritic copper powder, 23 wt% of acrylic acid modified waterborne polyurethane, 25.8 wt% of the solvent, 0.2 wt% of the silane coupling agent, 0.6 wt% of the carbodiimide and 0.4 wt% of the hindered phenol are weighed in the step (3) of the comparative example 9, the mixture is subjected to three-roll grinding treatment, is uniformly mixed and foamed at 1500rpm for 5min by a homogenizer to obtain the dendritic copper conductive adhesive, and the other preparation steps and materials are the same as those of the example 2.
The conductive tape prepared in comparative example 9 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 1.59X 10-5Omega m, shear strengthThe degree was 16.310MPa, the peel force (PI) was 10.3N/cm, and the adhesion force (PI) was 5B.
And (3) stability testing: after 1000h, the test of stability (test conditions of 25 ℃, 50% RH, 1atm) was carried out, and the volume resistivity was 6.12X 10-5Ω·m。
And (3) accelerated aging test: performing 1000h accelerated aging test in a constant temperature and humidity chamber (test conditions of 85 deg.C, 85% RH, 1atm) with volume resistivity of 8.77 × 10-3Omega. m, rate of change 5506%.
The volume resistivity is 1.14 multiplied by 10 in the alkali resistance test of soaking for 0.1MNaOH 10h-2Ω·m。
Comparative example 10
(1) Preparing antioxidant spherical copper powder: cleaning 3-10 micron commercial spherical copper powder with clean water, adopting 16g/L sodium formate as a corrosion inhibitor and 0.940g/mL N, N-dimethylformamide as a polar solvent, carrying out sealed reaction in a pressure-resistant container at the temperature of 150 ℃ for 18h, carrying out antioxidant modification treatment, then placing the obtained product at the temperature of 60 ℃, drying the obtained product under a vacuum condition for later use, and sieving the obtained product to obtain antioxidant spherical copper powder;
(2) weighing 50 wt% of the antioxidant spherical copper powder, 23 wt% of polycarbonate modified waterborne polyurethane resin, 25.8 wt% of solvent, 0.2 wt% of silane coupling agent, 0.6 wt% of carbodiimide and 0.4 wt% of hindered phenol, carrying out three-roll grinding treatment, and uniformly mixing and foaming by a homogenizer at 1500rpm for 5min to obtain spherical copper conductive adhesive, wherein the spherical copper conductive adhesive is shown in figure 5;
(3) coating the spherical copper conductive adhesive on a PET release film substrate by using a slit coating machine, and placing the PET release film substrate in an oven at 100 ℃ for 5-10 min to obtain a spherical copper conductive adhesive tape after surface curing;
(4) in the process of using the conductive adhesive tape, the conductive adhesive tape is torn off from a PET release film and placed on a PI film for hot pressing, wherein the hot pressing condition is 3-5 MPa, the temperature is 120-140 ℃, and the hot pressing time is 60-70 min.
The conductive tape prepared in comparative example 10 was subjected to a performance test, and had a thickness of 75 μm, no conductivity, a shear strength of 15.875MPa, a peel force (PI) of 9.8N/cm, and an adhesion force (PI) of 5B.
Comparative example 11
(1) Preparing antioxidant flaky copper powder: cleaning 3-10 micron commercial flake copper powder with clean water, adopting 16g/L of sodium formate as a corrosion inhibitor and 0.940g/mL of N, N-dimethylformamide as a polar solvent, carrying out sealed reaction in a pressure-resistant container at the temperature of 150 ℃ for 18h, carrying out antioxidant modification treatment, then placing the obtained product at the temperature of 60 ℃, drying the obtained product under a vacuum condition for later use, and sieving the obtained product to obtain antioxidant flake copper powder;
(2) weighing 50 wt% of the antioxidant flake copper powder, 23 wt% of polycarbonate modified waterborne polyurethane resin, 25.8 wt% of solvent, 0.2 wt% of silane coupling agent, 0.6 wt% of carbodiimide and 0.4 wt% of hindered phenol, carrying out three-roll grinding treatment, and uniformly mixing and foaming at 1500rpm for 5min by a homogenizer to obtain flake copper conductive adhesive, wherein the components are shown in figure 6;
(3) coating the flake copper conductive adhesive on a PET release film substrate by using a slit coating machine, and placing the PET release film substrate in an oven at 100 ℃ for 5-10 min to solidify the surface to obtain a flake copper conductive adhesive tape;
(4) in the process of using the conductive adhesive tape, the conductive adhesive tape is torn off from a PET release film and placed on a PI film for hot pressing, wherein the hot pressing condition is 3-5 MPa, the temperature is 120-140 ℃, and the hot pressing time is 60-70 min.
The conductive tape prepared in comparative example 11 was subjected to a performance test, and had a thickness of 75 μm and a volume resistivity of 4.55X 10-4Omega. m, a shear strength of 15.055MPa, a peel force (PI) of 9.9N/cm and an adhesion (PI) of 5B.
And (3) stability testing: after 1000h, the test of stability (test conditions of 25 ℃, 50% RH, 1atm) was carried out, and the volume resistivity was 7.92X 10-4Ω·m。
Accelerated aging test: performing 1000h accelerated aging test in a constant temperature and humidity chamber (test conditions of 85 deg.C, 85% RH, 1atm) with volume resistivity of 5.12 × 10-3Ω · m, change rate 1025%.
Alkali resistance test: the volume resistivity is 8.58 multiplied by 10 in the alkali resistance test of soaking for 0.1M NaOH 10h-4Ω·m。
TABLE 2
Figure BDA0003079933300000161
Figure BDA0003079933300000171
Table 2 shows the performance test, stability test, aging resistance test, and alkali resistance test parameters of the conductive tapes prepared in comparative examples 1 to 11. As can be seen, the conductivity and stability of the conductive adhesive tape prepared by the unmodified dendritic copper powder, the thiol-modified antioxidant dendritic copper powder and the imidazole-modified antioxidant dendritic copper powder are lower than those of the conductive adhesive tape prepared by the method provided by the invention. Meanwhile, the anti-oxidation copper powder with different morphologies has different conductivity at different contact sites in the polycarbonate modified waterborne polyurethane resin, so that the dendritic shape provided by the invention is optimal. The epoxy resin serving as the resin can provide good mechanical properties, but the electric conductivity and the stability of the epoxy resin are poor, the electric conduction adhesive tape cured by using the phenolic resin as the resin is brittle and does not have the adhesive tape characteristics, the initial electric conductivity of polyurethane resins of different types serving as the resin after thermal curing has a certain difference compared with that of the electric conduction adhesive tape prepared by using the polycarbonate modified waterborne polyurethane provided by the invention, and the stability, the aging resistance and the alkali resistance of the electric conduction adhesive tape are poor in the subsequent steps.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify the above-described embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of the invention should be determined from the following claims.

Claims (9)

1. A conductive paste, comprising: 15-50 wt% of copper material, 20-35 wt% of water-based binder, 0-6 wt% of assistant and the balance of solvent; the copper material is a copper material at least decorated with formate on the surface, the copper material is in a dendritic structure, and the aqueous binder is polycarbonate modified aqueous polyurethane.
2. The conductive adhesive according to claim 1, wherein the surface of the copper material is further modified with thiol.
3. The conductive adhesive according to claim 1, wherein the auxiliary agent is one or both of a silane coupling agent and a resin stabilizer.
4. An electrically conductive adhesive tape comprising a substrate and the electrically conductive adhesive according to any one of claims 1 to 3 coated on one or both surfaces of the substrate.
5. A preparation method of a conductive adhesive is characterized by comprising the following steps:
s1: performing anti-oxidation treatment, namely putting the copper material into a solution containing a corrosion inhibitor, performing sealing reaction at the temperature of 20-300 ℃, and cleaning and drying to obtain an anti-oxidation copper material; the corrosion inhibitor at least contains one or two of formic acid and formate;
s2: preparing the antioxidant copper conductive adhesive, namely weighing 20-35 wt% of a water-based binder, 0-6 wt% of an auxiliary agent, 15-50 wt% of the antioxidant copper material obtained in the step S1 and the balance of a solvent by mass percentage, and mixing and foaming to obtain the antioxidant copper conductive adhesive, wherein the water-based binder is polycarbonate modified waterborne polyurethane; the copper material in the step S1 is a dendritic copper material; the preparation method of the dendritic copper material comprises the following steps: copper is used as an anode, titanium is used as a cathode and is placed in electrolyte for electrolysis, and dendritic copper materials are collected on the cathode.
6. The method for preparing the conductive adhesive according to claim 5, wherein the formate is at least one selected from lithium formate, sodium formate, magnesium formate, aluminum trimethyl carbonate, potassium formate, ammonium formate, calcium formate, zinc formate, iron formate, copper formate, barium formate, beryllium formate, nickel formate, cobalt formate, and manganese formate.
7. The method of claim 5, wherein the corrosion inhibitor further comprises a thiol.
8. The method for preparing a conductive adhesive according to claim 7, wherein the thiol is at least one selected from the group consisting of methyl thiol, ethyl thiol, ethylene glycol thiol, dodecyl thiol, hexadecyl thiol, 1-propyl thiol, 1, 3-propanedithiol, mercaptoethanol, mercaptopyridine and derivatives thereof, cysteine, glutathione, and mercaptoethylamine.
9. A method for preparing a conductive adhesive tape, comprising:
s1: performing anti-oxidation treatment, namely putting the copper material into a solution containing a corrosion inhibitor, performing sealing reaction at the temperature of 20-300 ℃, and cleaning and drying to obtain an anti-oxidation copper material; the corrosion inhibitor at least contains one or two of formic acid and formate;
s2: preparing the antioxidant copper conductive adhesive, namely weighing 20-35 wt% of a water-based binder, 0-6 wt% of an auxiliary agent, 15-50 wt% of the antioxidant copper material obtained in the step S1 and the balance of a solvent by mass percentage, and mixing and foaming to obtain the antioxidant copper conductive adhesive, wherein the water-based binder is polycarbonate modified waterborne polyurethane; the copper material in the step S1 is a dendritic copper material; the preparation method of the dendritic copper material comprises the following steps: placing copper as an anode and titanium as a cathode in electrolyte for electrolysis, and collecting dendritic copper materials on the cathode;
s3: and (4) preparing the antioxidant copper conductive adhesive tape, namely coating, printing, preheating and curing the antioxidant copper conductive adhesive obtained in the step S2 to obtain the antioxidant copper conductive adhesive tape.
CN202110563863.XA 2021-05-24 2021-05-24 Conductive adhesive, conductive adhesive tape and preparation method thereof Active CN113480963B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110563863.XA CN113480963B (en) 2021-05-24 2021-05-24 Conductive adhesive, conductive adhesive tape and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110563863.XA CN113480963B (en) 2021-05-24 2021-05-24 Conductive adhesive, conductive adhesive tape and preparation method thereof

Publications (2)

Publication Number Publication Date
CN113480963A CN113480963A (en) 2021-10-08
CN113480963B true CN113480963B (en) 2022-06-07

Family

ID=77933085

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110563863.XA Active CN113480963B (en) 2021-05-24 2021-05-24 Conductive adhesive, conductive adhesive tape and preparation method thereof

Country Status (1)

Country Link
CN (1) CN113480963B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114023486A (en) * 2021-10-20 2022-02-08 西安理工大学 Environment-friendly micro-nano composite waterborne conductive silver paste and preparation method thereof
CN115656288A (en) * 2022-10-20 2023-01-31 嘉庚创新实验室 Foamy copper with surface coated with nano copper and application of foamy copper as enzyme-free glucose detection sensor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014010524A1 (en) * 2012-07-11 2014-01-16 タツタ電線株式会社 Curable electroconductive adhesive composition, electromagnetic shielding film, electroconductive adhesive film, adhesion method, and circuit board
CN104928724A (en) * 2015-07-07 2015-09-23 昆明理工大学 Method for electrolytically preparing dendritic fine copper powder in oxalic acid
CN111799012A (en) * 2020-06-23 2020-10-20 厦门大学 Antioxidant copper material and preparation method thereof

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107622833A (en) * 2011-05-18 2018-01-23 户田工业株式会社 The manufacture method and conductive coating of conductive coating
CN107513311B (en) * 2017-08-28 2020-03-06 厦门大学 Antioxidant copper-graphene composite conductive ink and preparation method thereof
CN109161358A (en) * 2018-07-25 2019-01-08 佛山腾鲤新能源科技有限公司 A kind of preparation method of conducting resinl

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014010524A1 (en) * 2012-07-11 2014-01-16 タツタ電線株式会社 Curable electroconductive adhesive composition, electromagnetic shielding film, electroconductive adhesive film, adhesion method, and circuit board
CN104928724A (en) * 2015-07-07 2015-09-23 昆明理工大学 Method for electrolytically preparing dendritic fine copper powder in oxalic acid
CN111799012A (en) * 2020-06-23 2020-10-20 厦门大学 Antioxidant copper material and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
聚碳酸酯二醇型水性聚氨酯胶粘剂的研究;杜辉等;《中国胶粘剂》;20080830;第第17卷卷(第08期);第1-4页 *

Also Published As

Publication number Publication date
CN113480963A (en) 2021-10-08

Similar Documents

Publication Publication Date Title
CN113480963B (en) Conductive adhesive, conductive adhesive tape and preparation method thereof
CN107337965B (en) Preparation method of antioxidant copper-based conductive ink
JP5151902B2 (en) Anisotropic conductive film
CN100335582C (en) Wiring-connecting material and wiring-connected board production process using the same
JP5644067B2 (en) Insulation coated conductive particles
CN101897245B (en) Circuit connecting material and structure for connecting circuit member
CN102786908A (en) Adhesive composition, circuit connecting material, connection structure of circuit member, and semiconductor device
CN107513311B (en) Antioxidant copper-graphene composite conductive ink and preparation method thereof
CN101142292A (en) Adhesive, adhesive for connecting circuit, connecting body and semiconductor device
CN109705803B (en) Single-component organic silicon conductive adhesive and preparation method and application thereof
CN104106182B (en) Anisotropic conductive connecting material, connection structural bodies, the manufacturing method of connection structural bodies and connection method
CN102559077A (en) Usage of adhesive film as circuit-connecting material and usage of adhesive film in manufacturing circuit-connecting material
JP2011060502A (en) Conductive particle with insulating particles, anisotropic conductive material, and connection structure
JP2011040189A (en) Conductive particle, anisotropic conductive material, and connection structure
KR20190009852A (en) Conductive material
CN114178523B (en) Method for producing surface-treated copper microparticles
JP5946978B1 (en) Conductive particle, method for producing conductive particle, conductive material, and connection structure
US20160329122A1 (en) Conductive paste and conductive film
JP4236856B2 (en) Anisotropic conductive adhesive and heat seal connector
CN105981228B (en) Method for manufacturing mounting body and anisotropic conductive film
JP5273514B2 (en) Electrode connecting adhesive and method for producing the same
CN109735239B (en) Conductive adhesive for anti-aging solar laminated tile assembly and preparation method thereof
JP2013149774A (en) Anisotropic conductive material, connection structure and method for producing connection structure
CN103374204A (en) Epoxy resin composite material, film and circuit substrate
CN103102816A (en) Anisotropic conductive film and semiconductor device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant